OK, clearly got myself thoroughly confused about these animals. Just been going through my notes and the animals I've mentally assigned to Indotestudo elongata were apparently labelled as 'Cyclemys mouhotii' (which is what is now Pyxidea mouhotii or Cuora mouhotii - I'm not the only one confused, clearly!).
I don't remember ever seeing mouhotii this big, which is my only defence!