Foreign currency earned overseas before domicile

Suppose I will immigrate from Hong Kong to UK on 1 Jan 2025 and become UK domicile afterwards. I transfer Hong Kong dollars 1000K, generated from salary in Hong Kong before 2025, to a UK bank on 2 Jan 2025. I exchange 500K Hong Kong dollars to British Pounds on 1 Feb 2025. Any tax needed to pay? Income tax or capital gain?

Hi
There are no tax implications for transferring savings to a UK bank account unless they generate interest or dividends. 
These would then potentially be subject to tax. 
Further guidance can be found here: 
Tax on savings interest
Tax on dividends