Waterhouse experience has been quite different for me.
Been visiting them for a number of years and spent quite a lot of money with them. However, I recently gave them a terrible (but honest) review as a result of a very surly assistant, and they have now refused further bookings from me!!!! I am told (by them I may add) that they are rated highly in a poll of the best MB repairers.
Quite easy to achieve a good rating if you ban customers who give you bad reviews!!!
If they are the best, God help us.
Labour rate is less than most Merc garages, but as the saying goes "you get what you pay for"