Hi,
UK residents are required to declare their worldwide income in the UK through Self Assessment. Please see link below.
Tax on foreign income: Overview
You meet Self Assessment criteria as you were in receipt of foreign income for tax year 2022 to 2023. If not already done so you should now register for Self Assessment. As your UK employer continued to pay you whilst on maternity leave then all income and tax will be included on your P60 for the year and should be included in your Self Assessment return.
Thank you.