I got this one completely wrong. It's one of the BP Casts I picked up recently.
While waiting for other figures to dry I decided to get on with this vehicle as it seemed to be just a variant on the BT. On finishing it in my standard Russian paint scheme, I checked the web and found the BT 42 was a Finnish variant, using 18 captured BT 7 chassis's and mounting a British 4.5" howitzer. I don't have any Finns and rather than repainting it I'll use it as a BT 7A , which mounted a 76mm howitzer. The other problem was that my usual dark brown wash also dried quite dark and has hidden some of the detail rather than highlighting it.