Your income from the date you arrived in the UK, is taxable in the UK on the arising basis.
The bonus was paid in 22/23 tax year, so will need to be included in your 22/23 tax return as foreign employment income.
You can claim Foreign Tax Credit Relief for the Hong Kong tax.
You will need to use the official exchange rates at the time you received the bonus, which can be found at:
Exchange rates from HMRC in CSV and XML format