Bernard, thanks so much for the information about Sowerby! As I'm sure everyone realizes by now, I have heaps to learn about English glass. I never knew anything about it before joining this forum; the only European glass I'd done much "research" into was Bohemian (and it still baffles me!

).
I looked for Simon's book - it's not available through ILL here, and having just bought 3 books (two from the Dudley Museum) I'm not yet ready to buy it yet. After a little Googling and reading it seems like cut glass wasn't much of a focus there, though of course that doesn't mean they didn't do it. These decanters are very well cut, and my feeling is that they would have been made by a company that was big in the cutting business, even if not in their total glass output. Bernard, when you say, "it is more likely that Leni's decanters were made in Manchester or Gateshead" do you mean there are other companies around there besides Sowerby that are also likely candidates?
Surprisingly (to me), Hajdamach says on pg. 359, "English cut glass formed the bulk of glass production in the late Victorian period and the profits from its sale helped to finance the technically complex art glass." Not so surprising is the fact that companies like Stevens and Williams employed freelance cutters to help meet their demands, so even if a company seems small on paper it may in reality have had more people working for it. Pound-for-pound (kilo-for-kilo

) it may not have produced as much as a company like Sowerby, but much of Sowerby's output was cheaper and more quickly made.
Of course, there's always the possibility Leni's decanters aren't English at all. Hawkes and Hoare are two good American candidates. Leni, what color do they fluoresce in UV?
Your green tazza is gorgeous! Thanks for posting it. You mention Sowerby's green...one little factoid I stumbled on was that Sowerby exported some of their colored glass, including to America. That's not necessarily relevant to the attribution on your compote, it just struck me as interesting. I learn so much through this board!

Does anyone have an example of Sowerby's cut glass? Or if some of it is shown in Simon's or another book, I would very much appreciate it if someone could email me an image or two. My curiosity is piqued now!!