I just replaced my rear shoks and springs, the driver side spring was broken and the suspension retaining bit that goes after the thread at the top of the strut had blown through due to the load with out the spring, The worst thing is that i took it to mercedes croydon and they said that it was all fine, but everytime in went over a small pot hole the car would wobble badly ad make a awfull banging noise, so i juat went ahead and got the whole lot and changed it myself, only to find the problem, the process took me 2 hours. Then i went back to mercedes croydon, who said they only did a visual check and that cost me £120ish but to me it was no good but they gave me a full refund after i made some noise. but in retrospect i should have got uprated or aftermarket set-up.
I've used MB Croydon in the past, but the MB Mitcham Service Center has a higher Customer Service Indicator rating. The guys at Mitcham are very helpful, and they are now my first point of call rather than Croydon.
Mitcham changed the NSR spring on the C Class a couple of months before the warranty ran out. Their tech was driving the car listening out for front suspension bush wear when he heard a noise from the rear spring.