Hi Andy,
I am not aware of RAF or RN having any of these Fords. There were three body types within the contract, E2 was a Binned Stores Vehicle, E3 was the Ambulance, with bodywrk very simialr to the E2 and lastly, E4 was a Light Anti-Aircraft Tractor, with 5 ton winch. The contract was dated July 1951. I think the last version in service with the Army, was the Binned Stores, a vehicle type which would generally only go out on exercise as it was not a general service type. My guess is that most would have been disposed of by the mid 1970's. there was a Binned Stores at Beltring this year and I believe the there is a similar one in the REME Historic Collection. There was a LAA Tractor in a museum in the North of England if I recall.
Andy, I see you are confused about whether Ford or Fordson is a different vehicle, my memory say that the badge on the front was actually "Thames", the army literature calls them Ford and the makes parts book says EnFo !