They diagnosed a failed fuel pump on my Roadster.
Charged me 4 hours labour ... Mercedes' time is an hour and a half, when challenged was told that there was no way it could be done in the time quoted by MB. Got the car back & I could smell fuel with a full tank, particularly when the roof was back, took it back. They looked at the car, told me it was cos I was 'over fuelling it'and the wet around the locking collar wasn't fuel
Very dismissive, I was wrong .... they were right.
I replaced the O ring from between the fuel pump & tank myself ... common sense suggests it would have been done when the pump was changed ... no more smell of fuel.