Flying LHR to PVG (on BA) and after 2 days flying on from PVG to HKG (on China Eastern). After 3 days in Hong Kong returning to PVG (on China Eastern) and after just under 3 days in Shanghai returning from PVG to LHR (via BA). I have a UK passport and printed details of all the flights. Looks to me that I can use TWOV twice in Shanghai but would appreciate confirmation. Thank you.