Range from the cheapest Downlights installation £290 (B&B London Construction Ltd based in EN1) to the dearest Downlights installation £440 (Foryou Electrical Ltd based in EN3).
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 EN3.