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.

[Darren] According to the online dictionaries I just consulted, "escalate" is a back-formation from "escalator".

[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.

[Projoy] By that token, anyone outside London should be able to have it done for £1.50, then.

[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!