Shack 1
If memory has not gone too far in the mists of time ,the Shackleton 1Was I think; BSF and BA ,I should think all the other marks were the same .
I read that the problems between the Canadian and British Merlins was the wiring looms the Brits had “Breeze “ type bulkhead plugs , the Canadian American they didn’t have a spare loom so had to swop looms ( not a quick job)