Now I've got well into chapter 2 I've started getting regular crashes usually towards the end of battles - I mean the game just stops and I am dumped straight to desktop, no error message.

If I reload to the previous save and replay the battle it always crashes, 100% so far, at roughly the same stage of the battle.

If I go back to an earlier save and replay everything up to the same battle it might work. Otherwise it seems i have to go back to an even earlier save and replay even more, etc until I find a save that does work.

This is getting unplayable - any ideas what's going on or how to mitigate against this?