P.R. Chinese passport holder, residing in UK with a UK permanent residence card. Need Visa for HK

I am a P.R. Chinese passport holder, residing in the UK with a UK permanent residence card.

I am planning a holiday in Hong Kong and Shenzhen.

I would like to fly from the UK to Hong Kong and stay in Hong Kong for 4 days and go to ShenZhen for 4 days and come back to Hong Kong for another 3 days and fly back to the UK. Do I need a Hong Kong travel permit/transit or not, please?