1.If you are Chinese (not a HK borned English or something etc.), even you have an British Passport, you can still apply a 回鄉咭.
2. Fill up a form and bring your HKID and passport photo for application.
P.S 1) when you fill up the form for your Nationality, remember is Chinese instead of British, otherwise your application will be rejected; 2) Background of passport photo is Pink.