Are we qualified for the 144-hour Visa Free Transit?

My wife (S. H. Chong-Tea), I (K. G. Chong) and friends are flying from London Heathrow Airport to Singapore (via Hong Kong) by Cathay Pacific in Mid-April to join the Sapphire Princes Cruises on 25.04.2016. We will arrive in Shanghai with the Cruises on 12.05.2016 and will be staying at a Hotel in shanghai for three days with the purpose of visiting places of interest in Shanghai before flying back from Pudong Int'l Airport (Shanghai) by the same Airline to London Heathrow Airport via Hong Kong Int'l Airport (transit) on 16.05.16. All of us are U.K. passport holders.