Range from the cheapest Downlights installation £210 (Nightowl Security Services based in RH5) to the dearest Downlights installation £390 (EPG Domestic based in KT24).
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 Bookham.