Range from the cheapest Downlights installation £260 (Carpencom Ltd based in EN11) to the dearest Downlights installation £440 (1st Electrical contractors based in EN9).
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 EN11.