Will we need a visa for 3 nights in Shanghai and 3 nights in Sanya, and if so which one?

My husband and I are British and taking a holiday to Shanghai for 3 nights before moving on to singapore for 3 nights, Hong Kong for 2 nights then to Sanya for 3 nights, then back to Hong Kong for a flight back to the Uk. Will we require it? Our flight lands in shanghai at 6am and departs 3 days later, at13.55. I have read about 72 hour free transit but this will exeed the time limit!