Self Assessment tax returns in Ty-isaf

Anyone in Ty-isaf who has been told to file a return: the self-employed, landlords with one or several properties, company directors taking dividends, people earning over £100,000 or repaying Child Benefit through the High Income charge, and those with capital gains, foreign income or untaxed savings interest to report.

• SA100 and every supplementary page you need (self-employment, UK property, dividends, capital gains, foreign income)
• A reconciliation against your HMRC personal tax account so nothing is missed or double counted
• Payments on account calculated and a one-page payment schedule sent to you
• Claims for allowable expenses, pension relief, Gift Aid and the trading allowance checked before filing
• Reminders at 60, 30 and 7 days before the 31 January deadline
• HMRC correspondence about the return we filed handled at no extra charge

1. Tell us your situation

   A short message or call about what you do and what needs filing. We ask the questions that determine the right package and nothing more.

2. Fixed fee in writing

   You receive one price for the work, confirmed by email before anything starts. It does not change if the job takes longer than we expected.

3. Send records, review the draft

   Records come by WhatsApp or email. We prepare the draft, explain the figures in plain English and answer your questions.

4. We file, you get the receipts

   Once you approve and the fee is settled, we submit electronically and forward the HMRC or Companies House acknowledgement the same day.

Ty-isaf is in Wales, Wales. Welsh taxpayers pay Welsh rates of income tax, set by the Senedd and currently matching the English bands, collected under a C-prefixed tax code. National Insurance, VAT and Corporation Tax are UK-wide. Property purchases in Wales pay Land Transaction Tax to the Welsh Revenue Authority rather than Stamp Duty, with its own bands and rates.

The Self Assessment calendar

The tax year runs from 6 April to 5 April. Anyone new to Self Assessment must register by 5 October after the end of the tax year in which their untaxed income began. The online return and the balancing payment are due by 31 January, with a second payment on account on 31 July where they apply. Paper returns have an earlier deadline of 31 October and are rarely sensible.

Payments on account

A common surprise in Self Assessment is the January payment that is far larger than expected. That is the balancing payment for the year just ended plus the first payment on account for the year ahead, which HMRC sets at half of the bill just calculated. We put the figure in your hands months ahead and tell you how to adjust it legitimately when circumstances change.

Late filing penalties

HMRC's penalties for a late Self Assessment return are automatic: £100 the day after 31 January, £10 a day from three months late up to £900, then the greater of £300 or 5% of the tax at six and twelve months. Interest and separate late-payment penalties apply to the tax itself. Companies House charges £150 to £1,500 for late accounts, doubling for a second consecutive year.

Making Tax Digital for Income Tax

Making Tax Digital for Income Tax began in April 2026 for sole traders and landlords with qualifying income over £50,000, extends to those over £30,000 in April 2027 and is planned for £20,000 in April 2028. It requires digital records in compatible software and four quarterly updates to HMRC each year, with a final declaration replacing the traditional return. Payment dates are unchanged.

The VAT registration threshold

Watching the rolling twelve-month turnover figure is one of the quiet jobs of monthly bookkeeping, because the £90,000 VAT threshold arrives silently. Crossing it brings quarterly returns, Making Tax Digital software and a decision about schemes. Crossing it late brings a bill for VAT you could not recover from customers and a penalty for failing to notify.

Corporation Tax rates and marginal relief

Corporation Tax is not a flat rate. Profits to £50,000 pay 19%, profits above £250,000 pay 25%, and the band between is taxed at an effective marginal rate of 26.5% through the marginal relief mechanism. Associated companies share the thresholds, which catches directors who own more than one company and is the most common cause of underpaid tax in owner-managed groups.

Salary versus dividends

Directors of their own companies usually take a salary at or just above the National Insurance thresholds, which keeps the year qualifying for State Pension and is deductible for Corporation Tax, with further income as dividends. Dividends above the £500 allowance are taxed at 10.75%, 35.75% and 39.35% by band and can only be paid from distributable profits after tax, with a minute and voucher each time.