It is now time to change from my nine-year old BMW 525 diesel. I am retired and do about 4000 miles per year. I do lots of short journeys of around seven miles, with very occasional longer trips. The dealer recommends the new 520 diesel. They do not really have an axe to grind as I would buy a petrol engine model if diesel is not suitable. The diesel is cheaper to buy, and tax and fuel consumption, although not terribly important, is better. I am concerned as to the problems with the particulate filter although they say it should not be a problem. The 520d is also recommended as the best buy in the motoring press. I would appreciate your thoughts.