Hello Dianaa,
I've been hoping someone would reply and give a better answer than i can. I can say these are definatley fitted to MOD vehicles. As for a time when they were fitted i'm not so sure. I do remember reading something about these being used on the 10 cwt trailers, so i alway thought they were wartime. Saying that i'm very keen on bedford MW's and in the parts list there no mention of a trailer socket being fitted, unless its described as something else and i am over looking it. At the same time i have the wiring removed from the back of bedford mw's and they all contain this socket.
This is the wiring, but wether they have been fitted at the factory or as part of the truck rebuild after the war i'm not sure.
Here is another type of the same thing, not sure what the difference is? This has got a WD marking similar to other electric items.
Again on this one same type of thing, not sure what truck it is off
