If, after submitting your VAT return, you discover that you have made a mistake, make an effort not to freak out! You should be able to either personally amend the problem or report it to HMRC in order to get it fixed. This straightforward manual explains what actions to take in either of the two scenarios.
Source: https://accountingfirmsinuk.blogspot.com/2022/09/how-to-correct-vat-errors.html