It depends when you sell it. If you intend on holding on to the car for a lengthy period of time - say another 4-6 years - having an independent specialist rather than a Mercedes-Benz dealership won't make too much difference to the resale value, especially if you're selling it privately.

If you plan on selling it sooner and especially if you decide to trade it in, then having a Mercedes-Benz service history will make a difference of probably a few hundred pounds. It seems silly, but unfortunately that's how people perceive a full service history. In our experience, independent specialists are not only better value, but also offer better service and have more expertise. After all, they can't merely rely on the main dealer badge above the door.