This bad boy arrived today, scored off of the bay (as if you hadn't guessed) for half the price of a Taiwanese imitation, although I don't think they do a knock off of this particular light...... yet!
Listed in the very brief description as for a C15, I don't reckon it is 250 AJS/Matchless seems to ring a distant bell but that's not a definite. If anybody knows for sure please let me know.
The description didn't say it was NOS but it's hard to believe it's spent much time fitted to a bike, this is how it arrived with no attempt to clean it up, no signs of rust on the back plate and not a hint of fading in the lens.
Easy to imagine that it was designed by the same guy that did the WIPAC Sabrina posted on here a little while ago, all fifties starship dreaming style. They seemed to be far more adventurous in their designs over at Wico-Pacy than their compatriots over at Lucas.