Finally the engine is back in the frame. New seals in the cambox, new bearings for the vertical shaft, a new gudgeon pin and new valve spring top clips. Bigend and main bearings appear to be OK and were left well alone. I would have fitted new valves and guides if I could have got them in time, they will do for another season. Fitted the BTH magneto.
At least I can start the engine to see what it does, no disasters should happen.