Many thanks all for the input, much appreciated. Brian - actually I hadn't realised Escape was a brand of trailer, thought the name was a play on escapism
Iowa Dave - the old shop guys are exactly who I was after by posting on the net
appreciate the pointers.
This is indeed a Euro-style trailer - I'm in London (and not the one in Canada!). I've had some similar input from elsewhere, apparently this coupling is likely to be off of a small British caravan from the 70s
It's in the bin now and a new one is on order...
P.S. Kudos on the cross-continental trailer knowledge!