They are either very very good
As the other half found out last week, she was met from a delayed arriving Dragon Air flight and fast tracked to the next available LHR flight, 30 min connection.
Or very bad as I had a missed connection with Dragon Air and was told there ''maybe'' a flight in the next day or two..Paid for my own flight home the next day on another airline.

But to the OP, why not PVG to LHR, the train from Huangzhou is only a few hours to PVG?

I could have got a train to Pvg and taken one of the many flights available