Can I claim an expense this year that I forgot to claim last year?

I have just renewed my landlord insurance for the year. When checking back to see exactly how I had categorised it in my accounts last year, I realised I had forgotten to record it. So my SA return under-reported my expenses. When I come to complete my tax return for 2023-24 in due course, can I add the cost of that previous policy, as well as the new one? It's a little over £400 in each year. Or do I just accept that I messed up last year and I paid slightly too much tax?

Hi,

You can still amend your 2021/22 tax return up to 31 January 2024 and your 2022/23 tax return up to 31 January 2025. You can do this online in your personal tax account or by submitting an amendment in writing.  

If it is too late to amend your tax return, you can submit an overpayment relief claim, by following the guidance here:

SACM12150 - Overpayment relief: Form of claims

Thank you