CT600 resubmission via the HMRC CT online filing service within permited amendment period

CT600 for the first period of accounts after the company formation was submitted via the HMRC Corporation Tax online filing service on 1/07/2023. The accounts were made up to 31 October 2022. However, instead of two periods, 13/10/21-12/10/22 (full year) and the short period to 31/10/22, only the first period (full year) has been filled via the HMRC Corporation Tax online filing service. I have proceeded with another submission to include the short period 13/10/22-31/10/22, as it has not been filed so far. Now, the HMRC Corporation Tax online filing service has opened two tax returns 13/10/21-12/10/22 (full year) again, and 13/10/22 - 31/10/22. Since the accounts have been made up to 31/10/2022, the income was overstated in the original filing, as it should have been apportioned between the two corporation tax returns to reflect the long period of accounts correctly. Therefore an amendment to the first year is required. My question is, if I make another CT600 submission for the period 13/10/2021 - 12/10/2022 with correctly apportioned income, will the second submission 'override' the original submission made on 1/7/2023? Or do I have to make an 'amendment' instead?

Hi Donna,
You can submit another CT600 for the 12 month period you have detailed and this will be classed as an amendment to the original CT600 submitted.
Thank you.