I expect main dealer costs could easily be diagnosis £150 ish, part £150 ish (depending on model) and labour £150 ish (if they charge 1 hour minimum). Quickly turns expensive when compared to SpikyMikeys costs of £87!
Seems to vary whether your local indie will charge for diagnosis. The one I use locally in Lancashire will do it free sometimes and sometimes charge £45, but well worth it. A good local indie will easily be worth a 40 mile trip in normal circumstances, and with a 9 year old car I wouldn't be going anywhere near an MB dealer myself. Difficult in your specific circumstances, since proper diagnosis on Star may avoid you throwing money away on unnecessary bits. I'd hunt around a bit to see if there are any local MB indies who could help.
