Completing a tax return involves more than entering a few figures into an online form. Income must be declared correctly, allowable expenses need to be identified and any tax reliefs must be claimed in accordance with HMRC rules. Missing information or using incorrect figures can lead to an inaccurate tax bill, penalties or enquiries from HMRC.

Professional tax return services help individuals and business owners complete their returns correctly and on time. SAS Accountants provides practical support throughout the process, from reviewing financial records to calculating the liability and submitting the completed return.

What Are Tax Return Services?

Tax return services involve preparing and submitting a return to HM Revenue and Customs on behalf of a taxpayer. The work normally begins with understanding the individual’s circumstances and identifying every relevant source of income.

The accountant then reviews the available documents, calculates taxable income, considers allowable deductions and prepares the appropriate return. Once the figures have been checked and approved by the client, the return can be submitted electronically to HMRC.

A professional service should also explain the resulting tax liability, the payment deadline and whether payments on account will apply for the following year.

Who May Need to Submit a Tax Return?

Self-employed individuals generally need to complete a Self Assessment return when their gross trading income exceeds £1,000 during the tax year. Business partners and people with taxable gains may also need to file.

A return may also be required when someone receives untaxed income from property, dividends, savings, commission, tips or overseas sources. Individuals liable for the High Income Child Benefit Charge may need to submit a return when the charge is not collected through PAYE.

Being employed does not necessarily remove the requirement. A person may receive a salary through PAYE while also operating a side business, letting property or receiving investment income.

HMRC provides further details in its guidance explaining who must submit a Self Assessment tax return.

Tax Return Services for Sole Traders

Sole traders must calculate the taxable profit generated by their business. This normally means deducting allowable business expenses from trading income.

Qualifying expenses may include materials, stock, professional fees, business insurance, advertising, software and certain travel costs. However, personal expenses cannot be deducted simply because they were paid from the business bank account.

Some costs have both business and private use. In these situations, only the qualifying business proportion should normally be claimed. Working-from-home costs, vehicle expenses and mobile-phone bills are common examples.

SAS Accountants can review the records, identify allowable expenditure and prepare a clear profit calculation. This helps the client understand how the final tax figure has been reached.

Tax Returns for Landlords

Landlords may need to report rental income from houses, flats, commercial units, holiday accommodation or land. The return should include the rent received and any allowable property expenses.

Potential deductions may include letting-agent fees, insurance, accountancy charges and qualifying repairs. Capital improvements are normally treated differently from routine repairs, while residential mortgage-interest costs are subject to specific tax-credit rules for individual landlords.

The tax position may become more complicated when a property is jointly owned, used personally for part of the year or transferred between owners.

Professional tax return services can help landlords calculate taxable rental profit and ensure that property income is not overlooked.

Company Directors and Tax Returns

Company directors do not automatically need to submit a tax return solely because they hold that position. However, a return may be required when a director receives untaxed income, substantial dividends, rental income, taxable gains or other amounts not dealt with fully through PAYE.

Director remuneration can involve salary, dividends, benefits and payments through a director’s loan account. Each item may have a different tax treatment.

SAS Accountants can review the director’s company and personal records together, reducing the risk of figures being missed or reported inconsistently.

Declaring Side Income and Online Earnings

More people now earn money through freelance work, online selling, consulting, delivery services, content creation and digital platforms. Depending on the nature and amount of the income, these activities may need to be declared.

Occasionally selling personal belongings is not necessarily the same as trading. However, regularly buying goods for resale, producing items for profit or providing paid services may amount to a taxable business activity.

Digital platforms may provide seller information to tax authorities under reporting rules. Keeping accurate records is therefore important, even when an activity begins as a small side project.

An accountant can review the circumstances and explain whether registration and reporting are required.

The Tax Return Deadlines for 2025/26

The 2025/26 tax year ran from 6 April 2025 to 5 April 2026. Individuals who need to register for Self Assessment for the first time should normally notify HMRC by 5 October 2026.

Paper tax returns must usually reach HMRC by 31 October 2026. The deadline for online returns is 31 January 2027, and any Self Assessment tax due must generally be paid by the same date.

Where payments on account apply, the second instalment is normally due on 31 July. The latest information is available in HMRC’s Self Assessment deadline guidance.

Preparing the return early does not normally bring the tax payment deadline forward. Instead, it confirms the amount due and provides more time to budget.

Understanding Payments on Account

Payments on account are advance payments towards the following tax year’s liability. They can surprise people submitting their first tax return because the January payment may cover both the previous year’s balance and an instalment towards the next year.

A second instalment is normally payable in July. Any remaining balance is then settled after the next return is completed.

Where income is genuinely expected to fall, it may be possible to apply to reduce the payments. However, reducing them without reasonable grounds may result in interest if the final liability is higher.

Professional tax return services should explain payments on account before the return is submitted so that the client understands the total amount payable.

What Happens When a Tax Return Is Late?

HMRC normally issues an initial £100 penalty when a required Self Assessment return is filed late. After three months, daily penalties of £10 can apply for up to 90 days. Further charges may arise after six and twelve months.

Separate penalties and interest can apply when the tax itself is paid late. An overdue return should therefore be dealt with promptly, even when the taxpayer cannot immediately pay the full liability. The current penalty structure is explained in HMRC’s Self Assessment penalty guidance.

If there is a reasonable excuse for missing a deadline, it may be possible to appeal. The circumstances and supporting evidence should be reviewed carefully before an appeal is submitted.

Common Tax Return Mistakes

Frequent mistakes include leaving out savings interest, forgetting income from a side business and claiming personal costs as business expenses. Taxpayers may also use figures from the wrong period or enter estimated amounts without suitable evidence.

Other errors involve omitted pension contributions, Gift Aid donations, student-loan information, property income, dividends or Capital Gains Tax details.

Some mistakes reduce the tax bill incorrectly, while others cause the taxpayer to pay more than necessary. A professional review can identify inconsistencies before the return reaches HMRC.

What Information Is Needed?

The records required will depend on the taxpayer’s circumstances. They may include employment documents, invoices, receipts, bank statements, dividend vouchers, pension details and records of savings interest.

Landlords may need rental statements, mortgage-interest certificates, agent statements and repair invoices. Individuals who sold property, shares or other valuable assets may need purchase documents, valuations and evidence of disposal costs.

Providing organised records allows the return to be prepared more efficiently. Where documents are missing, SAS Accountants can help identify what information may be available from employers, banks, investment platforms or previous advisers.

Why Use Professional Tax Return Services?

Preparing a return without professional help may appear to save money, but errors can become costly. Incorrect expense claims, omitted income and missed deadlines can all lead to additional tax, interest and penalties.

An accountant can check the complete financial position rather than focusing only on the most obvious source of income. Professional support can also identify legitimate allowances or reliefs that the taxpayer may not have considered.

Perhaps most importantly, the client receives a clear explanation of the calculation. This makes it easier to budget for tax and plan for the following year.

Tax Return Services from SAS Accountants

SAS Accountants provides professional tax return services for sole traders, landlords, company directors, investors and individuals with additional sources of income.

We can help organise financial records, calculate taxable income, review allowable expenses and prepare the required return. Our team can also explain the tax liability, payments on account and relevant deadlines before submission.

Whether you are completing your first return, managing several income sources or dealing with an overdue submission, SAS Accountants can provide clear and practical assistance.

Visit SAS Accountants or call 0330 133 0278 to discuss your tax return requirements.

Frequently Asked Questions
1. How do I know whether I need to submit a tax return?

You may need to file if you are self-employed, receive rental or overseas income, make taxable capital gains or have other income that has not been taxed fully through PAYE. HMRC may also issue a notice requiring you to submit a return.

2. What documents should I give my accountant?

You should provide records covering all relevant income and expenses. These may include invoices, receipts, bank statements, employment documents, rental statements, dividend vouchers and details of pension contributions or asset disposals.

3. Can SAS Accountants submit my return to HMRC?

Yes. Once the figures have been prepared, checked and approved by you, SAS Accountants can submit the completed return electronically to HMRC as your authorised agent.

4. Can SAS Accountants help with a late tax return?

Yes. We can help prepare the outstanding return, calculate the amount due and review any penalties. If you have a reasonable excuse for filing late, we can also help assess the available information.

5. Will using an accountant reduce my tax bill?

An accountant cannot remove tax that is legally due, but professional preparation can ensure that allowable expenses and valid tax reliefs are considered. It can also prevent costly mistakes and help you plan for future liabilities.