Hi,
No you cannot add this to a 2022 to 2023 tax return. Each tax year needs to be looked at separately. Although it is too late to amend your 2019 to 2020 tax return, you can still claim, in writing, 'overpayment relief' for 2019 to 2020, up to 5 April 2024.
Please follw the guidance below to ensure you use the correct formatting for claiming overpayment relief.
SACM12150 - Overpayment relief: Form of claims
Thank you.