Charged interest after filing SA for 2023/24

I just completed my SA for 2023/24 and after 24 hrs of the date updation, An interest was applied citing reason of overdue tax payment from July to Sep 2024. The fact that in SA i had to fill in the foreign income information which only becomes available by September in my home country, there was no way I could have completed the SA by July 2024. For e.g. by Sep 2024 I would know from my home country if the taxes that I paid there should be used as relief for UK SA or not. So if the taxes are returned then i cannot use that as tax relief in UK. So my question is why does HMRC levy interest when the final date of filling the SA for 2023/24 is 31 Jan 2025? How can I appeal (if i can appeal) for this interest that has been applied to me?

Hi,
This interest is most likely due on your Payments on Account.
If you reduced your Payments on Account for 23/24 prior to filing that return, but the Payments on Account we'd initially calculated were correct, interest is charged on the difference.
If you would like to object to the interest calculated, please do so in writing, to the address found here - Self Assessment: general enquiries
Thank you.