Hi All, Iv'e been glancing through the UK flyforums on this post. Latex gloves are certainly a very good liner, for whatever you're going to wear. I wore some about three days ago, on a typically cold Shropshire day and felt comfortable.
I suppose it depends on what you want really. I think Sealskinz could certainly help the Cold Weather Fly Fisher. Especially in extremes of temperature.
Iv'e e-mailed Sealskinz for some measurements and dimensions, so I'll see what turns up, then let you all know.