Hi travelwongc,
There are no Income Tax implications on the receipt of a cash gift unless the cash gift generates interest or dividends.
These would then potentially be subject to tax.
Further guidance can be found here:
Tax on savings interest.
If the money being transferred from your Hong Kong bank account to the UK was earned in a tax year that you were resident in the UK, then it will be taxable.
If it was earned in a tax year you were not resident in the UK, then it would be classed as capital and would not be taxable.
Thank you.