I see Jaffe Rose were a British Importer based in London from 1939-91 and largely
imported Czech glassware, including paperweights and vases with controlled bubbles, which would tie in with the weight in question.
I gather Jaffe Rose, whilst largely importing from Czechoslovakia appear to have imported glass from a number of countries, although looking at the comments at the bottom of the below thread, I see Chris mentions that these weights are well documented as Czech in origin.http://www.glassmessages.com/index.php/topic,44148.0.html
Just reading the last post as crossed posted. Seeing as they now appear to have been produced by a number of different companies it looks like attributing a specific manufacturer may be difficult, although for now presumably Czech or Italian in origin and imported by Jaffe Rose.
Thanks all for your comments, any other thoughts most welcome.