I live in London and plan to visit family in Beijing in the summer.

I plan to fly direct from London to Beijing for a week and then go onto Bangkok. However, the return flight from Bangkok has a 10 hour layover in Beijing. Would I be ok if I got the regular single entry visa for my first trip and then the 72hour free transit whilst in transit? I would like to leave the airport and go somewhere for lunch.
Any help would be much appreciated