Thanks. No-one seems to offer an on-line quote; I'm not even after anything as scientific as that, just an estimate of how many thousands of pounds it's likely to be so we can budget for it. Very frustrating.
[rab] How many windows do you want replacing? I have a ballpark figure of £5K for my flat, which would be 4 windows replacing, including patio doors. But then I am in the London area.
[Raal] Nice to see a new face here. You look a bit like Raak, if I may say so. Anyway, that's interesting because the ones I checked showed the reverse!
[Projoy] We have seven windows in total: three of them quite large (about 2m2), two medium sized (1.25m2) and two wee ones (less than 1m2 apiece). We're not in a listed building, or a conservation area, thank goodness, so they can be made out of anything we like, as long as we respect the astragals etc. 5K was the kind of number that was floating around my mind, for some reason, but from what you say it might be a bit more than that.
I paid 3.5k a few years ago for a ground floor flat; four large windows (3+m2 and one medium (1.25m2) plus a front door and a back door. It's the doors that add a lot to the expense; several hundred pounds a pop. And of course small windows are disproportionately costly for their size. I'd hope your requirements would be cheaper than Projoy's - I bet patio doors incur a double expense, once for being doors, and once for being large windows. I admit, I'd still anticipate a cost of well over 4k.