Hard to deal with and more expensive
New Mercedes car purchases come with drive away insurance from MB (underwritten by Risk Transfer Limited). Its convenient since you only just got a registration on it. You are then suckered into converting that into a full policy, for convenience, as they already have all details. The cover offered is quite good, but they upsell some needed extras. You end up paying 50% more than elsewhere, but with better cover.
Then comes the hassle - they refuse to accept the No Claims Discount evidence, asked for a copy of other company insurance renewal quote that shows it(and competitor premiums), and then refused to accept even that or a self declaration.
Waste of time. I cancelled in the first month after they tried to nearly double the insurance.