As you say Richard, it's a bit ancient, but IIRC, it already had a 2 year history of comments that were few and far apart. Apologies if I'm mistaken.
I felt that a casual reader would have found the replies contradictory and confusing, when in fact they were pretty much all valid comments.
I came upon the thread in hunting for tips on window assembly and pitfalls as I'm planning to use double-glazing UPVC to make a frame for a solar panel. I've still got a lot of research to do, but it seems the ideal choice.
My dig at window prices wasn't aimed at the hard working sole tradesmen, but at the massive companies ripping everyone off legally and the cowboy builders who do the same, but often illegally.
BTW, I love the picture. It gave me a good laugh!
Cheers,
Ancient Basi