EN ROUTE TO OLYMPICS. No visa needed? Uk to Shanghai to TOKYO

On our way to the Olympics we are stopping off for about 30 hours in Shanghai.

We arrive In Shanghai 22 July at 0800 on BA from London,Uk
We depart Shanghai for Tokyo on Japan Airlines but still on same booking at 1400 on the 23 rd July.

We will be staying for one night near the Bund. AM I CORRECT IN THINKING WE NEED NO VISA, just six months on passports, landing cards, inform British airways at checkin desk and present ourselves to transit desk upon arrival at Shanghai? Thank you.