When it comes to self-assessments, most people fall into one of two groups.

The first group starts gathering information months in advance, keeps everything organised and submits their tax return without a hitch.

The second group spends January frantically searching through emails, bank statements and paperwork, trying to remember whether they received interest, dividends, pension income or rental income during the year.

If you’re in the second group, don’t worry – you’re certainly not alone.

At DNA Accountants, one of the biggest causes of delays in preparing tax returns isn’t complex tax rules. It’s missing information. In fact, many of the follow-up questions we ask clients could be avoided entirely with a simple tax return checklist.

Why your Self-Assessment Tax Return isn’t just about your P60

One of the most common misconceptions we see is:

“I’ve got my P60, so that’s everything you need.”

Unfortunately, it’s rarely that simple.

Depending on your circumstances, HMRC may also need details of:

• Bank interest
• Dividends
• Rental income
• Pension income
• Child Benefit
• Capital gains
• Gift Aid donations
• Pension contributions
• Cryptocurrency transactions
• CIS income
• Trust income

Missing just one of these can result in an incomplete tax return. While it may not always affect the amount of tax you have to pay, it could lead to delays, additional queries or potential issues with HMRC.

Don’t ignore HMRC Coding Notices 

Most employees never look at their tax code, but they should.

HMRC often uses PAYE tax codes to collect tax from previous years, as well as tax due on benefits, savings, interest, dividends and other income. This means your tax code may not simply reflect your personal allowance.

If you’ve received a coding notice from HMRC, it’s worth checking that the adjustments are correct. We’ve seen many cases where taxpayers have been paying too much tax, or where HMRC has included outdated information in a tax code.

A quick review of your coding notice can help identify issues before they become bigger problems. You can use the HMRC portal to do so here. 

The income sources most commonly forgotten 

Savings Interest

Many banks no longer send annual certificates automatically, making it easy to forget about interest earned throughout the year.

With HMRC receiving information directly from many banks and building societies, it’s becoming increasingly important that the figures reported on your tax return match the information held by HMRC. 

Even small amounts can need reporting to HMRC, particularly for higher-rate taxpayers.

 

Dividends

If you’re a company director, own shares, or invest through platforms such as Trading 212, Vanguard, Hargreaves Lansdown or Freetrade, don’t forget to include dividend income.

This is one of the most commonly overlooked areas of self-assessment. 

From the 2025/26 tax year onwards, HMRC is introducing additional reporting requirements for company directors and shareholders of close companies. Taxpayers may be required to provide further information about their directorships and shareholdings, including details of companies in which they hold a significant interest.

As a result, it is becoming increasingly important to keep accurate records of dividends received and any shareholdings held during the tax year, particularly where you are a director or shareholder of your own limited company.

Did you know? For the 2025/26 tax year, the first £500 of dividend income falls within the Dividend Allowance. Whilst this amount is tax-free, it still forms part of your taxable income and must be reported if you are required to complete a Self Assessment Tax Return.

If your income is taxed through PAYE and you receive less than £10,000 of dividends, you may not need to complete a Self Assessment Tax Return solely because of those dividends. Instead, HMRC may be able to collect any tax due by adjusting your tax code.

However, you must tell HMRC about the dividend income so they can determine whether a tax code adjustment is appropriate. If you’re unsure whether you need to file a tax return, it’s always worth checking with your accountant.

 

Child Benefit

Many families don’t realise that Child Benefit can create a tax charge for higher earners.

The person receiving the payments isn’t always the person who needs to report it on their tax return, which is why it’s important to tell your accountant if anyone in the household received Child Benefit.

 

Cryptocurrency

Sold Bitcoin?

Swapped Ethereum for Solana?

Used crypto to buy something online?

All of these could have tax implications.

Crypto is one of the fastest-growing areas of tax reporting and one of the easiest to overlook.

 

Landlords: Don’t just send the rental income

If you own rental property, your accountant will usually need more than just the rent received.

Useful information includes:

• Mortgage interest
• Letting agent fees
• Repairs and maintenance
• Service charges
• Insurance
• Utility costs paid by the landlord

If you’ve bought or sold a property during the year, don’t forget to provide the completion statements too > more on that below.

 

Selling a Property? Don’t forget the 60-Day reporting rules 

If you sell a UK residential property and make a taxable capital gain, you may need to report the disposal to HMRC and pay any Capital Gains Tax due within 60 days of completion.

This reporting requirement applies separately from your Tax Return and can catch many property owners by surprise.

If you have sold a residential property during the tax year, your accountant will usually need:

• The purchase completion statement
• The sale completion statement
• Details of any capital improvements made to the property
• Information about periods when the property was your main residence (if applicable)
• Details of any costs incurred during the purchase or sale, such as legal fees and Stamp Duty Land Tax

Missing the 60-day deadline can result in penalties and interest, so it’s important to seek advice as soon as a property sale completes.

Did you know? Even if you have already submitted a 60-day Capital Gains Tax return, the disposal will usually still need to be reported again on your Tax Return.

If you’re unfamiliar with the 60-day reporting rules, we’ve covered everything you need to know in our guide: Capital Gains Tax Reporting – What You Need to Know About the 60-Day Rule.

 

Self-Employed? Making Tax Digital is coming

The way sole traders and landlords report income to HMRC is changing.

Under Making Tax Digital for Income Tax (MTD IT):

• Individuals with qualifying income above £50,000 will be brought into the regime from April 2026
• The threshold falls to £30,000 from April 2027
• The threshold falls again to £20,000 from April 2028

This means digital record-keeping is becoming more important than ever.

If you’re still relying on a shoebox of receipts or a spreadsheet that hasn’t been updated for months, now is a great time to get organised.

 

The good news? Most Tax Return stress is preventable

Preparing your tax return doesn’t need to be stressful.

The easiest way to avoid delays, additional questions and last-minute panic is to gather your information throughout the year and work through a comprehensive checklist before submitting your records.

If you’re unsure whether something needs to be declared, tell your accountant anyway.

We’d much rather review information that turns out not to be relevant than discover something important has been missed.

 

Need help with your Tax Return?

At DNA Accountants, we help sole traders, landlords, company directors and individuals across the UK prepare accurate Self Assessment tax returns and stay compliant with HMRC requirements.

Not sure whether something needs to be included on your tax return? We’d much rather answer a question now than correct a mistake later. Get in touch with the DNA team, and we’ll be happy to help.