I was thinking £80 but after seeing some of the prices on here I am now wondering if half of this would be more likely accepted.
I probably would not be doing the windows and am not sure how long they would take to do.
depends what state the windows and doors are in......
do they have sticky builders tape on the frames
are there sticky residues from labels on the glass (or maybe the labels are still there)
any hard concrete residue
have you checked the condition of the windows are they scratched, marked etc, you should get a disclaimer anyway to protect you as if any debris is removed form the glass and damage found underneath, believe me you will get the blame,
if you take someone on to do this work, make sure they are insured
what are the builders rules and regulations, what methods do they allow to be used.
straight forward ins and out on a standard clean should range from £24 to £40 depending on the size of the windows. Builders clean in really poor condition I would treble the price.
If in doubt get a local windie to go and quote with you