Range from the cheapest Downlights installation £357 (Pimlico Electricians based in SW1V) 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 Belgravia.