Sorry, Anne, I can't help here re the label. When I was at Davidsons I had absolutely nothing to do with the sales or warehousing of the domestic (as against technical) products therefore labels were a closed book to me. That contrasts with Sowerbys where I was involved with practically everything!
Re the glass, Nazeing comes immediately to mind. Just before I left Davidsons, Nazeing acquired, rather indirectly, a strong influence there. Nazeing products, testing Davidsons market, perhaps???