Range from the cheapest window sill replacement £200 (Queen of Flatpacks based in EN10) to the dearest window sill replacement £550 (LT Electrics based in CM16).
Comparing carpenter & joiners estimates for replacing a window sill gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to replace a window sill in EN9 by posting a job with HaMuch and we will send it to carpenter & joiners in EN9.