Range from the cheapest replacement of a toilet float valve £35 (J M Plumbers based in SW8) to the dearest replacement of a float valve £85 (LUCO - London Utility Company based in W1W).
Comparing plumbers estimates for replacing a toilet float valve in the cistern tank 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 toilet float valve in SW1A by posting a job with HaMuch and we will send it to plumbers in SW1A.