I think I remember this weight from approx. 5 years ago. I purchased a group of 3 or 4 weights Vasart/Strathearn from an auction house in Chichester West Sussex. I think all of the weights had a small KB scratched on the base and at that time I decided they were probably the initials of a previous owner, but that was only a guess. If memory serves the base of this weight was ground flat but not polished? The weight shown on Frank's brilliant site is the same weight, I remember sending Frank the picture.
Not much info. but hope its of interest to you.