'Even if it looked like William Walker 1992, you have to ask yourselves: "is it likely?". The reply should have been "No way"!'
Sorry Adam but I don't understand this comment from my own perspective.
I think for me personally, it's not possible that I know or remember all the work of particular makers that I've seen. Also I'm not a glass maker, so I really wouldn't have a clue if something would be considered an accomplished piece or not. I saw it and liked the shape (not the splotches as that's not my cup of tea admittedly) and tried to help with the signature. I was not aware this was not the type of work William Walker had been doing at that point. I was just trying to help 
m
Flying Free - Apologies if my comments appeared to be a criticism, this was not intended.
My knowledge base of signatures and glass identification comes from a life-time of collecting, selling,marketing and promoting mainly, but not exclusively, contemporary British glass, research, museum visits, studio visits and very little from the fact that I am also a glass maker. I also know more than the average about early English porcelain and other aspects of the decorative arts. But I’m not always correct!
My point was really about research from first principles. I think that the basic principles of research that apply to many disciplines can be applied to glass and other media. Interestingly, there was a programme on TV last night with Fiona Bruce and Philip Mould researching whether a so-called painting by Chagall was genuine or not.
What I was trying to say was that even if the signature had been clearly written and legible as William Walker, that this, per se, is not enough to establish that it is genuine. One would need to research whether a piece of this kind is likely to have come from William Walker’s hand at or around this date.
A quick search on William Walker Glass brings up this page,
http://iowstudioglass.wikidot.com/azurene which indicates that WW was an active designer in 1978 also this page
http://www.telegraph.co.uk/property/3354612/Artful-acts-of-creation.html where it states that WW is “Now 56, he tried one or two other jobs before discovering his craft at 24 and the article is dated 2006.
A bit of simple maths suggests in 1978 he was 28 and that he is now 64. Also that in 1992 he was 42 and assuming a continuous career had been working in glass for 18 years.
So in doing the research the next question is whether the piece looks like the work of someone who has been established for 18 years, bearing in mind that we are dealing with a craftsman who blew the glass for the restoration of Windsor Castle.
A further look down the google list brings one to this board
http://www.glassmessages.com/index.php?topic=47688.0 and a rather nice image of an eighties vase by William Walker, which looks very refined by comparison. This would make me wonder whether it was likely that an glass artist would move from this very refined form to the rather cruder, naïve form in six or seven years. There I would probably be making a valued judgment based on my experience of other media, and still with the room for error, would say no.
Hope this clarifies things.