Update. Now we have lost comms with the ECU. Grrrr. This happened before and unit was sent for testing and came back okay. We then isolated some loose wires and everything was okay. Once car is running (if SKIM isn't playing up) the car runs great. Although when driving all the dash modules (speedo, revs, fuel, oil pressure etc) can die when the SKIM light comes on. But car runs fine, providing it starts.
So I am beginning to suspect it's an ECU issue.