Range from the cheapest Downlights installation £356 (Emergency Electrician London 365 based in W1H) to the dearest Downlights installation £490 (Novalux Electrical Services Ltd based in SW1Y).
Comparing electricians estimates for Downlights installation 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 for installing downlights by posting a job to electricians in Mayfair.