R. K.

Thank you for your reply. Yes, I did as you suggest to make the amendment, (alhough I put the mortgage interest amount in box 44 which is the "Residential Property Finance Costs" box), however it didn't seem to accept this. As it's getting near to the deadline to submit the amendment online, I will put it in writing. Would you advise me to put all the details in a letter or do I need to fill in a form? Also, when writing do I need to provide all other figures for earnings or will HMRC be able to access this from my original submission.

When I filled out my tax return for 2021-22 I entered the £1000 in box 20.1 to make use of the Property Income Allowance as my expenses would have come to a lot less than this (ie £636). This made my Taxable profit £2980.00. However, I have only just realised that I could have also put down my mortgage interest costs (ie £1347) in box 44 so as to take advantage of the 20% tax relief off this figure. I've tried to go back into my 2021-22 SA105 form to make the amendment, but when I enter the figure in box 44 it doesn't allow me to make this claim. Can I therefore not claim the 20% tax relief on my property finance costs if I've claimed the £1000 Property Income Allowance? I understood that the 20% tax relief off Property Finance Costs is nothing to do with expenses.