Personal tax return preparation and filing
Self Assessment tax return accountant in Cardiff
We prepare complete UK tax returns for individuals, sole traders, landlords, directors and professionals with income or gains that must be brought together accurately.
Filing position
When a Self Assessment tax return may be required
The obligation follows the facts and any notice issued by HMRC. A return can still be required when no tax is due, and HMRC’s withdrawal of a notice should be confirmed rather than assumed.
Sole traders and consultants
Trading income, allowable business costs, capital allowances, basis-period adjustments and losses must be established from the records.
Landlords and property owners
Rental income, ownership shares, allowable expenses, residential finance costs and brought-forward property losses feed into the personal return.
Employees and directors
Employment income may need a return where benefits, expenses, dividends, director loans, untaxed income or other filing triggers apply.
Investors and asset owners
Dividends, savings, chargeable gains and relief claims can require filing even when some income has already been taxed at source.
International income
Residence, overseas income, foreign tax and treaty relief need to be considered before the foreign pages and tax credit are completed.
An HMRC notice or late return
A formal notice to file should be dealt with by its deadline. Earlier missing returns require a year-by-year review rather than one combined estimate.
Check the current official Self Assessment filing rules.
Complete return service
What our Self Assessment service includes
We first establish every relevant source of income, gain, deduction and tax already paid. The records are then reconciled and the correct supplementary pages prepared.
You receive the return, tax calculation and payment position for approval before filing. Where the calculation creates payments on account, these are shown separately from the balancing payment.
Included in the work
- filing and supplementary-page review;
- tailored document request;
- income and expense reconciliation;
- allowance and relief checks;
- tax calculation and payment summary;
- draft approval and online submission.
Annual timetable
Self Assessment deadlines and payments
The normal timetable is based on the tax year ending 5 April. A different date can apply when HMRC issues a late notice to file.
Notify HMRC
Register by 5 October after the tax year when a first return is required.
Paper return
The normal deadline for a paper return following the end of the tax year.
Online return and payment
The usual online filing date and due date for the balancing payment and first payment on account.
Second payment on account
The second advance instalment is normally due where payments on account apply.
Confirm the date for your year using HMRC’s Self Assessment deadline guidance.
Digital reporting
Making Tax Digital changes the record cycle for some sole traders and landlords
Making Tax Digital for Income Tax requires qualifying individuals to keep digital records, send quarterly summaries and complete the year-end tax return through compatible software.
The staged entry thresholds use gross qualifying income from self-employment and property before expenses: over £50,000 from April 2026, over £30,000 from April 2027 and over £20,000 from April 2028, subject to the detailed eligibility and exemption rules.
The annual return still matters
Quarterly updates do not settle the final liability. Other income, tax adjustments, reliefs and the final declaration remain part of the year-end process.
Check when MTD applies →Cardiff and South East Wales
One return can connect employment, a side business and property income
It is common for a professional or director to have PAYE income alongside consultancy work, dividends or a rental property. The return should reflect the actual ownership and activity rather than treating each source as an isolated form.
Welsh taxpayer status can affect the treatment of non-savings, non-dividend income, while savings and dividend rates remain UK-wide. The address and residence position should therefore be checked rather than inferred from where an employer is based.
Records commonly required
- P60, P45, benefits and pension statements;
- self-employment income and expense records;
- rental statements and property costs;
- interest and dividend certificates;
- disposal calculations and foreign tax evidence;
- payments already made to HMRC.
Connected tax work
Related services and calculations
These subjects remain separate pieces of work, but the underlying figures may need to agree.
Landlord tax returns
Rental accounts, property expenses and finance costs.
Open this page →Foreign income tax returns
Residence, overseas income and foreign tax relief.
Open this page →Capital Gains Tax
Property, shares, business assets and other disposals.
Open this page →Payments on account calculator
Estimate the balancing payment and advance instalments.
Open this page →Clear starting fee
Scope and price are agreed before work begins
A straightforward employment or pension return starts at £125 plus VAT. Self-employment starts at £300 plus VAT, with the final fee following turnover, records and additional income sources.
Common questions
Questions about self assessment tax return preparation
The answer can change with the period, records and connected transactions. These are the usual starting points.
Can you file a return after the 31 January deadline?
Yes. File it as soon as the records allow because further penalties and interest may continue. We also check the payment position and whether any earlier returns remain outstanding.
Do I need a tax return only because I am a company director?
Directorship alone does not automatically decide the position. Salary, dividends, benefits, untaxed income, gains and any HMRC notice must be considered.
Can you reduce payments on account?
A claim may be appropriate when the next year’s qualifying liability is genuinely expected to be lower. An excessive reduction can create interest, so the estimate should be supported.
Does the service include landlord or foreign pages?
They can be included when agreed in the scope. Property, foreign income and gains involve additional records and may carry separate fees.
Will I see the return before it is filed?
Yes. You receive the relevant return figures, calculation and payment information for review before authority is requested to submit it.