Depending on how old/residual value the car still has, don't discount BMW dealers themselves and ask for value service. Before you fall on the floor laughing it only cost me £30 more to have my 35is major service serviced by them as opposed to three Indies that I checked out. I can live with that and it preserves the Extended Warranty I have on the car. I grant you, a major issue and they'd charge mega bucks. But the value service - for cars over four years old - is worthy of at least some consideration.