Eastern Chan

Hi, I had migrated to UK with BNO visa in August 2021 and continued my original contract with my employer in Hong Kong as remote staff. My salary is paid in Hong Kong with Hong Kong Dollar. For taxation year 2021-2022, I have to pay income tax in Hong Kong as I was there from April to July 2021. Should I have tax return to HMRC for the income after I moved to UK in period August 2021 to March 2022? Or the income from this taxation year is considered taxed in Hong Kong and exempted for UK tax return under UK-Hong Kong tax treaty? Moreover, if I go to have tax return in UK by Self-Assessment, should only the take-home pay be considered? Part of my salary is deducted for Mandatory Provident Fund (MPF), which is a compulsory pension contribution in Hong Kong eligible for tax exemption. Thank you very much.