Stay away from the big names as they have salesman...team leaders and area managers along with advertising to pay for.
Cant you find a local supplier with a good reputation... ask friends for a recommendation.
Have a look localy for a glazing company that have been around for some years...dont go near Safestyle UK...( Buy one get one free.)..there's no such thing as free windows.They cut it to the bone and pay the fitters peanuts and overload them with work...not a good combination if you are after a reasonable job.
Personal recommendation is very useful, ask around your neighbours who've had it done. I took three quotes before I decided who to use for the DG in my house, well worth it, I went for a local company in the end and was very pleased with the work.
We had a quote for £14,000 for 8 windows, 1 front door with glass side panels and a patio door. We then had a quote from Anglian windows - £5,000! (being fitted next month)
I would say get a few quotes and some local recomendations.
We had Anglian about 15 years ago and our windows have to be packed with paper tissue to stop the draughts in high winds. I`ve tried extra draught excluder, but cant get any thick enough.
After an intensive search and 8 quotes i finally settled on Global Windows.I found them to be very efficient and with an excellant follow up service.They were reasonably priced but not the cheapest.
As previously said stay clear of BOGOFF they were my 8th quote and the most expensive.