Personally, if it's out of warranty then I would opt for an Indy.
You will get MB parts fitted if they are a good Indy.
You will pay less for labour.
You will get time-served MB trained mechanics if they are a good Indy rather than possibly paying huge rates for trainees under supervision.
Indy's depend on repeat business and word of mouth advertising rather than the corporate facade.
I use an Indy .........
Fantastic, thanks. Will definitely check out the indies then - I'm keen to keep the car as 'original' as poss with MB parts. Thanks for the info and for making me welcome to the forum.