Range from the cheapest Downlights installation £290 (Lee Electrical based in N2) to the dearest Downlights installation £490 (Volt based in N2).
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 N3.