Hah! I forgot to leave a bid

Had I bid, and won this one, I would have confirmed its UV reaction.
However, I am reasonably sure that it is from the same era as several others I have, which I put in the 1946-1955 Ysart Brothers (Vasart) period. My web page article on pre-56 Vasart weights has a
section on basal features and shows a few with a similar "button pontil mark" as on the eBay one. Also, although not obvious from my images, some of my YB weights have a similar "rusting" around the pontil mark.
Another point is that I have only seen one other broadly similar "YB scramble" weight (or is it two, or three???), so although this eBay one was a bit on the "untidy" side, it was an interesting example from my viewpoint.