This is getting even more interesting and informative......how good to have your definitive reply heronglass123. You mention it is imported, so I wonder if you are able to say where it was made?
You also mention that there is still a Heron Glass shop in Poole, do you have a web address for it please. I am very fond of Heron Glass as I collect glass birds and animals, and don't live too far from the Dorset border.