Range from the cheapest window sill replacement £260 (Building and Plastering Solution based in SE5) to the dearest window sill replacement £700 (F H Heating based in NW8).
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 W1C by posting a job with HaMuch and we will send it to carpenter & joiners in W1C.