i got asked to go and give a park owner a price about 2 years ago, i counted the windows and it came to 10 quid each home ( give or take a pound either way )
the park owner said that some guy does them off a pair of steps and charges £7.50 each
i didnt bother with coming down in price, if i had been short of work, i might have, as you wouldnt have any travel time between them and you will pick up a fair few
just wasnt for me