Tax Advice for Sole Traders, Small Businesses and Startups
A client rang me last winter in a slight panic. She'd had a letter from HMRC, hadn't understood a word of it, and had spent the previous evening trying — and failing — to get through to anyone on the HMRC helpline. "I just wanted to ask one simple question," she said, "and I ended up more confused than when I started." I hear some version of that story every month. Tax in the UK isn't complicated because people are bad with numbers. It's complicated because the system itself is layered, the guidance is scattered across dozens of GOV.UK pages, and getting a straight answer from the right person can feel like a full-time job on its own.
This guide is my attempt to cut through that. Below, I've answered the tax questions I'm asked most often by sole traders, small business owners, freelancers, landlords, and startups across Tunbridge Wells and the wider South East — in plain English, with real numbers, and without the usual runaround.
This confuses more people than you'd expect. HMRC can tell you what the rules are and process your tax affairs, but — and this is important — HMRC staff cannot advise you on how to arrange your finances to pay less tax, nor will they tell you which choice is best for your situation. That's not their job, and it's not really what they're set up to do. An accountant or tax adviser, on the other hand, works for you. We look at your specific circumstances and tell you what's genuinely in your best interest, including things HMRC would never volunteer, like a relief you're entitled to but haven't claimed.
If your question is "what do the rules say," HMRC is a reasonable starting point. If your question is "what should I actually do," you need an accountant.
The main self-assessment helpline is 0300 200 3310, and the general enquiries line is 0300 200 3300. Be honest with yourself about timing though — Monday mornings and the days either side of a deadline are dreadful for wait times. Wednesday afternoons tend to be quieter, in my experience. The HMRC app has also become genuinely useful for simple tasks like checking your tax code, viewing what you owe, or updating your address, without needing to speak to anyone at all.
You can get factual information — what a deadline is, what a form means, how a specific rule applies in a general sense. What you won't get is guidance tailored to your situation, or a recommendation on the most tax-efficient way to structure your affairs. HMRC's role is to administer the tax system fairly for everyone, not to help any individual pay less. That's a completely reasonable position for them to take, but it does mean you need someone else in your corner if you want proactive advice.
Yes, though patience helps. The webchat function on GOV.UK has improved and can resolve simpler queries without a phone call at all. For anything involving actual figures on your account, though, you'll usually still need to call or use your online personal tax account, where a growing number of things — checking payments, updating details, viewing correspondence — can be done without waiting in a queue at all.
This is one of the most searched tax questions we see, and it matters more than people realise. As a general rule, HMRC has four years from the end of the relevant tax year to raise an assessment for extra tax owed, where an error was made despite the taxpayer taking reasonable care. So, for example, any genuine mistake in your 2022/23 return would fall outside HMRC's reach after April 2027, provided reasonable care was taken.
That time limit extends, though, depending on behaviour:
The distinction between "careless" and "deliberate" is genuinely subjective, and it's exactly the kind of grey area where having an accountant argue your case properly can make a real difference to both the time limit that applies and the size of any penalty.
The biggest change landing in 2026 is Making Tax Digital for Income Tax, which becomes mandatory from April 2026 for self-employed individuals and landlords with qualifying income over £50,000. Instead of one annual self-assessment return, affected taxpayers must keep digital records and submit quarterly updates to HMRC, followed by a final declaration. It then extends to those earning over £30,000 from April 2027. If your turnover is anywhere near these thresholds, it's worth having a proper conversation with your accountant now rather than scrambling next spring — the record-keeping habits you'll need take time to bed in.
This one trips people up because it sounds related to the assessment time limit above, but it's a different rule entirely. Trading losses can generally be carried forward and set against future profits from the same trade with no fixed time limit, provided the trade continues. Where the four-year figure tends to come up is in claims and elections — many reliefs and claims, including certain loss relief claims, must themselves be made within four years of the end of the relevant tax year, or you lose the right to make them at all. It's a "use it or lose it" situation, which is exactly why leaving your tax return until the last fortnight of January is such a risky habit — you can run out of time to make a beneficial claim before you've even realised it was available.
Penalties follow the same time limits as assessments above — so up to 20 years in cases of deliberate wrongdoing. But there's a separate, more everyday penalty structure worth knowing: late filing penalties start at £100 the moment you miss a self-assessment deadline, rising to £10 a day after three months, with further charges at six and twelve months. None of this requires HMRC to prove carelessness or intent — it applies simply for being late, which is precisely why I tell every client the same thing every January: file even if you can't pay in full. The penalty for filing late is far steeper than the interest on paying late.
Age UK and TaxAid both offer free, genuinely helpful guidance for people over pension age with straightforward tax queries, and the Low Incomes Tax Reform Group publishes clear, jargon-free guides specifically aimed at pensioners. These are excellent starting points for simple questions. Where things get more complex — multiple pension sources, rental income alongside a state pension, or inheritance planning — that's where paid advice starts to earn its keep, because the free services generally aren't resourced to handle intricate, personal situations.
Here's where it gets genuinely interesting, and I say that as someone who didn't expect to find pensioner tax exciting until a few years ago. The personal allowance — the amount anyone can earn before paying income tax — is £12,570, and it's been frozen at that level since 2021, with the freeze now extended through April 2031. Meanwhile, the full new state pension has been rising each year under the triple lock and now sits at roughly £12,548 a year for 2026/27. That leaves a gap of only about £22 before other income — a small workplace pension, savings interest, anything — tips a pensioner into paying tax. A decade ago that gap was close to £3,000. It has genuinely never been this tight, and it means many more pensioners than in the past will find themselves paying at least a small amount of income tax, sometimes for the very first time in their lives.
For a pensioner with reasonably simple affairs — a state pension plus one or two private pensions — a one-off consultation or a simple self-assessment return often costs somewhere in the £150–£350 range. Where a pensioner has rental income, investments, or is thinking about inheritance tax planning, fees rise accordingly, but so does the value of getting proper advice, since the amounts at stake tend to be much larger.
Not automatically, and not just because someone reaches pension age. A tax return is generally required if you have income HMRC doesn't already know about or can't collect through your tax code — rental income, dividends above the allowance, or income from self-employment that's continued into retirement, for example. If your only income is the state pension and it currently sits below the personal allowance, you likely won't need to file. Given how close that gap has become, though, it's worth checking your position every year rather than assuming last year's answer still holds.
Inheritance tax is one area where I'll always be honest with a client about the limits of general advice. The nil-rate band — the amount you can leave before inheritance tax applies — has been frozen at £325,000 for a long time now, with an additional residence nil-rate band potentially available if you're passing on a home to direct descendants. But the moment a farm, a business, a trust, or a second property enters the picture, the rules multiply quickly, and this is genuinely an area where specialist knowledge pays for itself many times over.
If your estate is likely to fall well within the thresholds, and your situation is straightforward, your regular accountant can usually guide you through the basics. But if you're a business owner in Kent looking at business relief, or you own multiple properties, it's worth asking your accountant directly whether inheritance tax planning is something they handle regularly or something they'd refer out — a good accountant will tell you honestly either way, and the right answer isn't always "we'll do it ourselves."
The best time to start this conversation, in my experience, is well before you think you need to. I've sat with families who left it until a health scare forced the issue, and the options available shrink considerably once time is short.
I get asked about software constantly, usually by a business owner who's been recommended three different platforms by three different people and has no idea which one actually fits their business. A few things genuinely matter here. First, make sure whatever you choose is compatible with Making Tax Digital, since HMRC's digital requirements are only going to expand, not shrink, over the coming years. Second, think about how the software connects to your bank — automatic bank feeds save an enormous amount of manual entry, and manual entry is where errors creep in.
Xero, QuickBooks, and FreeAgent are the three platforms we see most often among Kent small businesses, and each has genuine strengths. Xero tends to suit businesses that want strong reporting and a wide range of add-on integrations. QuickBooks is often a comfortable choice for businesses migrating from older desktop software. FreeAgent, which comes free with certain business bank accounts, is popular with freelancers and very small limited companies who want something simple without a monthly fee. None of them is objectively "the best" — the right one depends on your business, your existing bank, and honestly, which one you'll actually enjoy opening every week rather than dreading.
This is where a genuinely good accountant earns their keep. A few areas worth reviewing every year:
None of these should be treated as a template to copy blindly. I've seen business owners follow generic advice from a forum that simply didn't apply to their circumstances, and it cost them more in the long run than doing nothing at all would have.
The list is broader than most people expect: business-related travel, a proportion of home running costs if you work from home, equipment and tools, professional insurance, marketing and website costs, training directly related to your trade, and accountancy fees themselves. The golden rule remains "wholly and exclusively" for business purposes — anything with a personal element needs a fair, defensible split.
If your self-employed income is under £1,000 a year, you may not need to declare it at all thanks to the trading allowance. Above that, you can choose to deduct the £1,000 allowance instead of itemising actual expenses, which suits people with very low costs relative to their income. For most established sole traders with genuine business expenses, claiming actual costs works out better — but it's worth running the comparison rather than assuming.
Receipts, invoices, bank statements, and — for anything involving a personal-business split like home costs or mileage — a clear, consistent method for calculating that split. HMRC doesn't expect perfection, but it does expect a reasonable, documented approach that you could explain if ever asked.
Registration becomes compulsory once your taxable turnover exceeds £90,000 in any rolling 12-month period, not just your accounting year — a distinction that catches people out. Below that threshold, registration is voluntary, and for some freelancers, particularly those working mainly with VAT-registered businesses who can reclaim the VAT themselves, voluntary registration can actually be worthwhile. It's a genuinely personal decision that deserves a proper conversation rather than a default yes or no.
The habit I recommend to every freelancer, without exception, is a separate savings account and a standing transfer of roughly 25–30% of each payment received the moment it lands. I had a client — a copywriter working with agencies across London and the South East — who adopted exactly this approach after a particularly stressful January, and she told me the following year's tax bill felt like a non-event for the first time in her freelance career. It's a small habit that removes an enormous amount of stress.
For HMRC's purposes, there generally isn't one — "freelancer" is simply the everyday term people use to describe self-employment in creative, consulting, or contract-based work. The tax treatment is identical to any other sole trader, unless you've set up a limited company, at which point different rules around corporation tax and director's pay come into play.
Good software tracks income and expenses in real time, categorises transactions automatically from bank feeds, and gives you a running estimate of your tax bill throughout the year rather than a single frightening number in January. That visibility alone changes how people plan — you can see a large tax bill coming months in advance instead of discovering it all at once.
Many platforms offer direct HMRC submission for self-assessment and, increasingly, for the quarterly updates required under Making Tax Digital. That said, submission is only as reliable as the data behind it — software won't catch a misclassified expense or a missed allowance on its own. That's still where a second, human pair of eyes adds genuine value.
Plenty of clients hand the day-to-day entry over to us entirely and simply forward receipts and invoices as they arrive. Others prefer to keep hands-on control and just want their accountant reviewing the figures periodically. Both are completely valid ways of working — the software should fit around how you actually want to run your business, not the other way round.
Allowable expenses include letting agent fees, landlord insurance, repairs and maintenance, ground rent and service charges, and accountancy fees for managing the property's tax affairs. What you can't claim for is capital improvements — replacing a small kitchen with a significantly larger, higher-specification one, for example, is treated differently from simply repairing what was already there, and getting that distinction wrong is one of the more common landlord tax mistakes I see.
This catches out landlords who haven't reviewed their position since the rules changed. Mortgage interest can no longer be deducted directly from rental income before calculating tax. Instead, landlords receive a tax credit equal to 20% of the mortgage interest paid, regardless of what tax band they're in. For higher-rate taxpayers in particular, this can mean paying considerably more tax than the old system produced, even where profit hasn't actually increased — which is exactly why so many landlords have been reassessing whether to hold property personally or through a limited company in recent years.
If you're earning rental income, you need to declare it to HMRC and typically register for self-assessment if you haven't already, though there's a small property allowance of £1,000 that may mean very minor rental income doesn't need declaring at all. Separately, some local authorities, including areas across Kent, operate landlord licensing schemes that are a legal requirement distinct from tax — worth checking with your local council alongside sorting out the tax side.
Selling an investment property usually triggers Capital Gains Tax on the increase in value since you bought it, and — importantly — this must be reported and paid to HMRC within 60 days of completion, not left until your next self-assessment return. I've had more than one landlord come to us after missing that 60-day window, and the interest and penalties involved make it a genuinely expensive mistake to make. If you're planning to sell, have the conversation with your accountant beforehand, not after the sale has already completed.
Tax rules shift every year, sometimes in ways that genuinely matter to your bottom line, and staying on top of all of it while also running a business is a lot to ask of anyone. That's what we're here for. Whether you're a sole trader in Tunbridge Wells trying to make sense of a letter from HMRC, a landlord weighing up mortgage interest relief, or a startup founder wondering whether now's the right time to bring in proper advice — we'd genuinely like to help. Contact us via our website here or get in touch directly, and let's have a straightforward conversation about where you stand.
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