i looked into this .
first you need to be on one link ! internet booking and authorisation service i think this costs arround 200 pounds per year.
i contacted motability and they confermed to me that they had agreements with the main dealers and all there work went to them.
but to be honast i worked in a vauxhall dealership for 18 years and from what i saw the dicounts that motability demanded as well as all the other lease companys made most of the work not worth doing.
motability even charge the dealer if there mot fail rate goes over a set amount ??
john