Sue — As always with hand-made glass — please let us have a close look at their bases, both baskets and stands. ... and the various joins in the stands. ... and the handles.
Have you looked at the similar epergnes (using the term loosely) in Gulliver? Be wary of his Richardson references, they are not intended to be attributions. As none of the English glass houses appear to have registered such a design, so you have assume that they all might have made them — and they probably did!
What base wear is there?
Like Leni, I prefer my glass to have never been properly cleaned. You can't fake years of grime. Fortunately something like 99% of British women (and men) have not a clue how to wash up and clean things properly. They're taught by their mothers that it is a chore, so cannot possibly do it properly. You can always tell a glassie by looking in their kitchens. If you see a huge array of cloths and brushes, of every shape and size ever made, including some that haven't been invented yet, you've found a fellow glassie!
Bernard C.