Hi Oakley,
You can pay any tax due on your 23/24 untaxed interest online, as well as through your code.
However, if you would still prefer to pay this tax via Self Assessment, contact us here:
Self Assessment: general enquiries
To allow us to register you to file a 23/24 return.
If you've already submitted a 23/24 return, you can amend this return with your untaxed interest figures via your Personal Tax Account.
The untaxed interest figures in your 24/25 code are estimates, based on your confirmed amounts from the previous year.
If you would like us to update these figures, contact us here:
Income Tax: general enquiries
Thank you.