Range from the cheapest Downlights installation £260 (John Wood based in ME8) to the dearest Downlights installation £380 (FY-Fused Automation based in ME7).
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 ME2.