Seems this is pretty normal on some bikes as they are fitted with protectors to stop the chain chewing away the swinging arm - moto cross bikes being a good example, but a lot of road bikes are the same.
Reckon I could make my own - just needs to be a piece of nylon sheet chamfered on one edge attached to the swinging arm as far as I can see.
Am I being too simplistic - or is there anything I need to consider?
Couldnt resist "riding" it - clocked up 2/10 of a mile on the private road at the back of our place.
Seemed to pull away pretty well and at least 1st & 2nd gears work.......so do the brakes.