Sorry it's difficult to tell from your photos how the 'eye' and trail were done? is it an applied blob with the trail, or does it have a blob in the middle of a circle of glass which is pulled down into a trail? or it is an indented oval shape with a trail that comes off it?
None of which answers would make it any clearer to me who did it, but knowing how the trail and eye were done may help in the future.
I think Stuart did a kind of plainer blob eye and trail but it's only a guess that the catalogue pics I have are Stuart. And I don't have any of this epergne unfortunately, they are all pics of vases.
Stevens and Williams also did do an applied eye and trail type thing.
If I get a chance I'll take some pics of the trails on my 'peacock eye ' pieces which are all different.
m