Thanks Mike. When I looked at Colin's images I did not take into account the size of the thing. I was looking more at the style of the swivel mounting on the hoop arrangement. I do not know whether that is a mounting unique to particular spot/search light manufacturers or whether it is a generic style.
It would be interesting to properly identify it and determine its provenance. Perhaps Colin has an annecdote from the seller of its origin to the seller.
I will canvas the image to some naval associates of mine.
In the mean time the romantic notion that it came off a submarine that attacked Bogies ship would be well fitting in Colin's night club shed talk around the bar.
Bob