For those of you with Hong Kong permanent ID card and a British driving licence, you may not be allow to drive in Hong Kong using your British driving licence as a 'visitor'.
In HKSAR v Tsui Pak Sun, Paxton and another (HCMA50/2016), the judge ruled that someone who enter Hong Kong with his Hong Kong permanent ID card cannot be class as a 'visitor' and therefore should not allow to use his foreign driving licence to drive in Hong Kong.
However, for those who enter Hong Kong with their foreign passports instead of their Hong Kong permanent ID card, the judge ruled that 'it would be wrong and illogical ... not to treat them as "visitors" '.
The judge's main points were outlined in paragraphs 33 and 35.
http://legalref.judiciary.hk/lrs/common/ju/ju_frame.jsp?DIS=106122&currpage=T