Hi
Please have a look at the guidance on joint ownership - tenants in common at
TSEM9220 - Ownership and income tax: legal background: joint ownership - tenants in common.
The UK / Hong Kong tax treaty give Hong Kong the taxing rights on property income arising from HK property.
It also allows HMRC to tax you on your share of the property income and for you to claim a tax credit for foreign tax paid.
You would do this by completing the property section and the the foreign section of the tax return (on paper, SA105 & SA106).
Thank you