Tempsford Glass. I contacted Naomi’s Stained Glass and asked her about it as had seen something similar on her FB page.
When I was reeducating myself about actually leading rather than copper foiling a piece I saw it used on there and remembered Naomi’s pictures.
I have to say, so far, so good, it’s brilliant. Have just ordered a second board as the window I am making will need two to get the width. I think it’s very well priced especially for the job it does.