Article 10 of the double taxation agreement refers to dividends. If the dividend is paid by a Hong Kong resident company, to a UK resident, may be taxed in the UK.
Article 11 of the double taxation agreement refers to interest. Interest paid in Hong Kong to a UK resident individual is only taxable in the UK.
In both instances, you should declare your overseas dividends and interest on a self assessment tax return, as both are taxable in the UK.
UK/HONG KONG DOUBLE TAXATION AGREEMENT AND PROTOCOL