I think that the 'peacock tail' vase has nothing to do with the glass we are talking about. Stylistically it bears no resemblance to 'peacock eye' glass. The piece in question is a typical piece of Victorian (continental) decorative glass, whilst the peacock eye glass has its stylistic look firmly rooted in the 20th Century, and illustrates the first tentative steps towards modernism (sort of).
The Webb’s trails, and designs, look very much like the pieces shown in Mervyn's book, as well as the examples posted on this message board. They do include a large tadpole-like blob that thins into a tail, which trails down the glass onto the base. They just don't have the internal 'eye' tool-work. My parents own a piece that has the same sort of trails, so I will post an image when possible.
My parents have quite a few pieces of peacock eye glass and there are a lot of variations between the pieces, indicating different makers. For instance, a piece that resembles the Webbs patterns has no eye tooling, but the trail is all one colour. Other pieces have no eye tooling, but the centre of the eye has a different colouration. Another piece has the head of the trail opening up into a fan shape that meets the rim of the glass. These are all signature features that would distinguish the work of one maker from another. Someone just has to do the research and look at all the pattern books etc.
When it comes to identification, Stuart's signed their pieces consistently form the 1930s and Webbs from 1907, so later pieces should be easy to attribute.
As for the Webbs pattern books............ to look for the patterns I had to take video footage that my father had filmed and convert it to DVD. I suppose I could try to find out how to get stills from the DVD, but there are copyright issues and limitations to the use of such material. The footage I looked at is far from complete and I’m sure that there are more examples in the records. These may well include details such as the name Webb’s gave to such wares. This might include the origins of the infamous Manley reference to ‘Cairngoram Drops’.