Unlike most sales and services, there isn't a definity ranking of which double glazers are the most reliable all around.
If anyone in the Midlands has had a local or national company successfully fit several uPVC windows, let us know how it went. I'm willing to pay a bit more for a local company to do it right.
FYI, I've had a local company C&A Windows around...waiting for a quote. I've decided against Amber windows due to obnoxious sales practices. Thought about Safestyle UK but read things that make my hair curl. This could be because they're crap or because they do so many installations. Waiting for www.windowquoter.co.uk to put me in touch with some local companies...but it's taking a lot longer than I'd have thought!