Quick answer: A self assessment tax return is HMRC's way of collecting income tax on earnings not taxed at source — self-employment, rental income, dividends and more. The online filing deadline is 31 January; missing it costs an automatic £100 penalty. Bayar Hughes & Co prepares and files your return from our New Eltham office or fully online, with a fixed quote agreed up front.
What Is a Self Assessment Tax Return?
Self assessment is the system HM Revenue & Customs (HMRC) uses to collect income tax from people whose income isn't automatically taxed through PAYE. If you're employed, your employer deducts tax before you're paid — but if you earn money as a sole trader, receive rent from a property, take dividends as a company director, or have other untaxed income, you must declare it yourself on an annual tax return.
Getting it right matters. An incorrect return can mean overpaying tax you'll never notice losing — or underpaying and facing HMRC enquiries, penalties and interest. That's why thousands of people across London hand their self assessment to an accountant rather than wrestle with it alone every January.
Who Needs to File a Self Assessment?
- Sole traders and the self-employed earning more than £1,000 in a tax year (before expenses)
- Landlords with rental income from property in the UK or abroad
- Company directors receiving dividends or other untaxed income
- Partners in a business partnership
- Higher earners — including those affected by the High Income Child Benefit Charge
- People with capital gains — for example after selling shares or a second property
- Anyone with foreign income, significant savings interest, or income from side hustles and online selling
Not sure whether you need to file? Ask us — a five-minute conversation is free, and far cheaper than an HMRC penalty.
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Key Deadlines and Penalties
| Date | What's due |
|---|---|
| 5 October | Register for self assessment if it's your first year |
| 31 October | Paper tax return deadline |
| 31 January | Online tax return deadline and payment of tax owed (plus first payment on account) |
| 31 July | Second payment on account, if applicable |
Miss the 31 January deadline and HMRC issues an automatic £100 fine — even if you owe no tax. After three months, daily penalties of £10 (up to £900) begin, with further penalties at six and twelve months, plus interest on unpaid tax. We make sure our clients never see one of these letters.
How We Reduce Your Tax Bill — Legitimately
The biggest hidden cost of DIY tax returns isn't the time — it's the allowances people don't know they can claim. Depending on your situation, we'll review:
- Business expenses: equipment, travel and mileage, phone and internet, professional fees
- Home-office costs for the self-employed and remote workers
- The trading allowance and property allowance
- Pension contributions and Gift Aid — often missed by higher-rate taxpayers
- Capital allowances on tools, vehicles and equipment
- Landlord-specific reliefs, including replacement of domestic items and finance-cost tax credits
Our Simple 4-Step Process
- Free consultation — by phone, WhatsApp, or at our New Eltham office. We confirm exactly what you need and quote a fixed fee.
- Send your records — securely online or drop them in. We'll tell you precisely what we need.
- We prepare and check your return — claiming every relief you're entitled to, and reviewing it with you before anything is submitted.
- We file with HMRC — you get confirmation, a copy for your records, and a clear statement of exactly what tax to pay and when.
Making Tax Digital Is Coming — Be Ready
From April 2026, Making Tax Digital for Income Tax begins for self-employed people and landlords with qualifying income over £50,000 — requiring digital record-keeping and quarterly updates to HMRC instead of one annual return. The threshold then drops to £30,000, bringing far more people into the system. As your accountants, we'll set up compliant software, handle the quarterly submissions, and make the transition painless.
Self Assessment Tax Returns Near You in South East London
Bayar Hughes & Co has served clients since 1991 from Green Lane Business Park in New Eltham (SE9), a short walk from New Eltham station. We work with individuals and businesses across Eltham, Mottingham, Sidcup, Chislehurst, Bromley, Bexley, Greenwich, Lewisham, Blackheath and Woolwich — and as online accountants for clients throughout London and the UK.
Frequently Asked Questions
When is the self assessment tax return deadline?
The deadline for online self assessment tax returns is 31 January following the end of the tax year, which also covers your first payment. Paper returns are due earlier, by 31 October. Missing the deadline triggers an automatic £100 HMRC penalty, with further penalties and interest the longer the return stays outstanding.
Who needs to file a self assessment tax return?
You usually need to file if you are self-employed as a sole trader earning over £1,000, a partner in a business partnership, a landlord with rental income, a company director taking dividends, a higher earner affected by the High Income Child Benefit Charge, or you have untaxed income such as capital gains, foreign income or side-hustle earnings.
How much does a self assessment accountant cost in London?
A straightforward self assessment tax return typically costs between £150 and £300 with a local accountancy firm, depending on complexity — rental properties, capital gains or foreign income add work. Bayar Hughes & Co provides a fixed, transparent quote up front before any work begins.
Can an accountant reduce my tax bill?
Often, yes. An experienced accountant makes sure you claim every allowance and deductible expense you are entitled to — from the trading allowance and mileage to home-office costs, pension contributions and capital allowances — while keeping your return fully HMRC-compliant.
Do you handle self assessment for clients outside New Eltham?
Yes. We meet clients at our New Eltham SE9 office and act as online accountants for clients across Eltham, Sidcup, Bromley, Greenwich, Lewisham, Bexley, the rest of London and the whole UK, using secure digital document sharing.