I said:
... and one reference book shows that some early Ysart canes also made their way, with legitimate reason, into at least one other glassworks.
Frank said:
The 'other' glassworks with Ysart canes was Perthshire Paperweights
My comment related to Bob Hall's book
Old English Paperweights, Chapter 10 Stevens and Williams. In that chapter, there is reference to "a cupful of millefiori canes" held in the Brierly Hill Glassworks museum and comment that parts of those canes have been matched to the set of Ysart [Salvador] canes illustrated in the book
Ysart Glass. Page 127 of Bob's book shows a selection of thirty three of those Brierly Hill Glassworks museum canes. I don't know if they are from, or are, the cupful, but I am sure that the majority are actually full, complete early Ysart canes. This fits with other comments in the book including the point that "several workers came from Scotland to learn glass making techniques in the 1960s and '70s".
There could, therefore, be some frigger weights made at Royal Brierly Crystal which have early Ysart canes but encased in glass that perhaps fluoresces differently from the known Scottish ones with Ysart canes.