UK Citizen with HKID. Which visa do I need?

I am currently a British Citizen (born in UK) holding a British passport. But I am also of Chinese descent, meaning that I have Hong Kong Permanent ID Card with the RO status (Right to Land, Hong Kong).

My question is, do I have to apply for the China Tourism Visa (L), as a British Citizen?

Or am I able to apply for the "Mainland Travel Permit for Hong Kong and Macao Residents" in the UK to enter China? If the latter; Can I apply for this in the UK?