Upvc window fitting - damage to plaster normal?

thebaldwindowfitter

we have come across this many times sometimes after you have discovered the first one is fitted like this the rest can be taken out by cutting the straps by cutting down with a sabre saw were frame meets plaster . No company can say that there will be no damage to internal finishes we have had whole chunks of plaster fall off due to existing walls skimmed over badly things happen

cosmiclabrat

As well as plaster damage (which I'm confident our fitters will make good -as they are considered a reputable company in our area) they have taken a lump out of one of the external stone mullions which is really obvious (about size of an open hand). They expect payment tomorrow on finishing the fitting - is it reasonable for me to expect them to replace it or if they don't and won't to withhold any payment until I get someone else to do and take the cost of the final settlement ? Any suggestions greatly appreciated