2012 15k give it a good run every 300 miles
Lol, I suppose it depends on your definition of a good run. For me, a good run
is 300 miles. Mine would never do less than the 35 miles from Thetford to the centre of Norwich. To me, that's a short trip and the car actually is warmed through.
Some of the guys I work with will drive from somewhere like Long Stratton to Norwich (8 miles) and they reckon that's enough to get the car warmed up. I'm not so sure. One person in the office with a C250 CDi drives from his flat by the art school to the train station (under 1 mile) and swears he doesn't think that's too short a journey for a diesel. Personally I think that's extreme mechanical abuse but his cars are very low mileage and people queue up to buy them at the end of the lease.
Diesels make zero sense unless you're doing serious mileages to get the benefit of the fuel economy. Or your company car policy says Diesel only. The DPFs absolutely hate short trips and it'll be interesting to see what happens to cars that are used for short journeys in terms of them racking up the regen cycles and needing replacing at what seem like very low mileages. I think the DPF is replaced at 120,000 miles or 8 years which fits with the 15,000 mile per year service intervals.
I would predict a whole bunch of unhappy 'low mileage' owners complaining loudly about having to replace relatively expensive DPFs at what seem like fairly low use. I think that DPFs will have to fall in price though like catalytic convertors did otherwise a huge number of 'banger' diesels will be uneconomic to repair. Things like the ordinary VWs, Peugeots, Fiats that will be £2500-ish at 8 years old but need a £1000 DPF simply won't be serviced to schedule.
Maybe my mileage is in the lower limits a diesel engine of this sort likes. Probably more usage from your part will be of benefit, of course after MB sort out your problem under guarantee 
