If the Astra with a DPF has variable servicing it is quite likely it may require frequent oil changes if the car isn't doing very regular long distance trips.

Despite me doing around 18,000 a year my DPF equipped X type never did more than 8,000 miles between oil changes (the shortest being 6,000!) and it was suffering other problems due to too many short hops in urban areas. This was the main reason I got rid of it.

As regards the sales staff, they sell cars and from my experience know very little about how they actually work. It is up to the buyer to ensure a car is fit for purpose and IMHO 12,000 a year with a short weekly motorway trip is not enough miles to justify a DPF diesel.

DPF diesels should be the preserve of the 30-50,000 miles a year sales rep.

Edited by daveyjp on 22/08/2011 at 12:14

Doing only 10,000 to 12,000 miles a year probably doesn't justify the extra purchase cost and then running cost of a diesel over a petrol - not just in servicing costs but tyres etc. Your mother-in-law also probably doesn't light the engine up enough with a good thrash on the motorway to clean it out.