London - Beijing - Bangkok - Chengdu - London

Good Afternoon,

We are looking looking at travelling from London to Bangkok with a 3 day stopover on the way out in Beijing, we will then stay in Thailand for about 2 weeks, then on the way home the flight comes via Chengdu and we would like to stop here for 2 days to see the Pandas.

Will we be eligible to use the 144hour transit visa in both directions or will we need to get a multiple entry visa ?

Many thanks