the window cleaning will be much more than the cleaning - windows id go for 30 £ an hr + as builders cleans are HARD WORK
cleaning kitchens etc i personalyy would quote same but i dont want to do it so i wouldnt be bothered if i got the work if you want the work it might be better charginbg around £15 but im sure the cleaners here will tell you better about that
personally for the windows id work out how long it was gonnna take me roughly ie 1.5 days then price at £25 an hour then stick on a extra day or so just in case! they are always more work than you expect often times double for windows if they are full of cement and stickers and need de taping etc
make sure you get a scratched glass waiver and report all scratches before they stitch you up for it - good luck