Range from the cheapest installation of an outside power socket £70 (Gsi-Gas based in SE5) to the dearest installation of a garden power socket £150 (Matrix Electrics based in SE21).
Comparing electricians estimates for installing an outside RCD socket 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 to install an outside power socket in SE22 by posting a job with HaMuch and we will send it to electricians in SE22.