thanks for your contributions - you're both far better at Walsh coloured/art glass than me, so can't really comment much on material other than cut glass. Could be wrong, but perhaps I'm getting the impression that cut glass is more likely to be found with a backstamp, as opposed to coloured material - but then again it may simply be that small backstamps are more difficult to see on coloured glass - when found they are almost always faint, though I do have a pair of finger bowls where the mark is very clear.
When you consider the factory's output, it's surprising that we don't see more pieces with a mark - if pushed suppose I could muster about a dozen pieces of marked clear cut glass - and then there is my blue Pompeian grapefruit which is marked, but it's the devil to see.
For me, it's stemware that seems to be the most commonly found items with a backstamp - 'Fruiting Vine' and 'Kenilworth' must have been popular in their day. Also worth remembering that the factory used a variety of Registered Trade marks over the years, some of which may not always be recognized as belonging to Walsh. As far as this mark is concerned, and its successor, perhaps the percentage of pieces stamped was fairly small.
My suggestion for the reasoning behind Bernard's thoughts - re the salt - may well have been due to Reynolds comments in his book 'The Glass of John Walsh Walsh'. Discussing the factory's closure in 1951, Eric Reynolds says ....... ""When Walsh closed, some of the tools, employees and their expertise were acquired by other Midlands glass manufacturers such as Tudor Crystal. However, they did not attempt to deceive the public and their pieces were clearly marked. For example, there are several pieces of Tudor glass decorated with the Walsh
Fruiting Vine
pattern or the Clyne Farquharson
Leaf pattern""
For the limited quantity of patterns made by both factories, and unmarked, now impossible to say who made what I'd imagine.
Collecting Walsh production, seriously, must be a daunting task - prodigious quantities and patterns - so perhaps no one does - thank goodness we do at least have Eric Reynolds book