Range from the cheapest Downlights installation £290 (Builder based in DA14) to the dearest Downlights installation £440 (Clear property management (Se) ltd based in Da2).
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 Swanley.