PCS in Horndean can do the job. They have a courtesy car too. Not local but Olly came to mind immediately.
Mercedes Benz & Smart Specialists | Prestige Car Service | Horndean, Hampshire
Send Olly a PM or better still give them a call (BlackC55)
cfoster said:Have you tried PMW in Chelmsford? They specialise in BMW/Merc, Pete (the owner) has worked on them for years, only place I would go other than main dealer.... worth a punt....
Gemtech come recommended
Mercedes Benz Service Repairs and Tuning Romford Essex