Range from the cheapest Downlights installation £290 (Flip The Switch Ltd based in SM4) to the dearest Downlights installation £540 (Hyland Heating based in SM3).
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 SM4.