Hi Dilwyn,
Thank you for posting the copy of the Pottery Gazette advert. It's very interesting as it brings up a few designs I've never seen (that I know of) such has Sea-shell glass, Caleri Glass, Rustic Glassware, Vandyke, and The "Incrusted" Art Glass Ware. Very interesting indeed.
I'm glad to hear that the blue colored Filigree fingercup is a rare one. An interesting story, a lady had a set of four of these for sale some time back. She had no idea what they were, but wanted about $800 for the set. I went in on them with a friend and my Mom, getting two for myself

Their very nice, and rarely seen. The cameo glass Filigree pieces I've only seen in the Charles Hajdamach British Glass book.
For my online article I'm planning to use examples from my collection of Jeweled Glass (Rd #55693, we also call it zipper glass in the U.S.), Tapestry Glass, Osiris Glass, Northwood Pull-up, Filigree/Latticino Glass, and some of their threaded mother-of-pearl air trap zipper pieces. If you have anything from the Stevens & Williams catalogs on these types of glass that you can share, I'd love to see it.
I looked through the Corning Museum's online Library index, and it appears that they have the Stevens & Williams catalogs lumped together. For instance: Description books, no. 21-24. Ware 23415-28001, Stevens & Williams Brierley Hill Glass Works Staffordshire, England 1897. I am checking to see if they will allow an inter-library loan of the microfiche. It would be fantastic, and what an excellent resource if someone would publish these catalogs. I wonder why it hasn't been done?
Also I see that you're working on a book on Webb Burmese. I believe I have one of the Webb Burmese color variants (lilac maybe?). I have about 30 examples of Webb Burmese, and this piece is colored like no other I've ever seen. I also have a decorated rose bowl in what we would call unfired Burmese (white). I can get some pictures this weekend if you'd be interested in seeing them.
Thanks,
Brian