As for the "lilac cane", as seen on Richard's site, I would have no problem with that cane being made at the Ysart Bros company (or even pre-war). And the weight on Richard's site looks quite untidily set, which could indicate Ysart Bros work rather than Vasart Ltd or later.
But, as ever, lots of the Ysart canes were used over a very long time, so the existance of an early cane cannot be used alone as a suggestion of a period in which a weight was made.