The "cheap" installer may not have to pay VAT, may not have a flashy van to pay, may not have premises, may live round the corner etc.. so vastly lower overheads.
I couldn't afford you Dan with all your toys![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I couldn't afford you Dan with all your toys