Hi Eric,
Caithness were bought by a company called Dartington Glass in 2006, they had to slim the company down to make it more efficient and profitable so most of the staff were made redundant, including Calum Anton, and had to find other work. I will ask a few people I know and if I can find where Calum is now I will let you know. A much smaller glassworks was set up in Crieff, next to the old Perthshire factory, in 2008 and is there today
As I mentioned previously, a lot of Caithness staff made one of a kind pieces for the Scottish Glass Society Annual Exhibition each year and these were only ever signed with their name, the title of the piece and usually the year. Hopefully one of our GMB colleagues may have one of Calum's signed weights for you to compare the signature
Dave