Does the diesel have a DPF (Diesel Particle Filter) ? Only reason I ask is because I'm having problems with my Kia. It's down to the car only doing short journeys and the engine not heating up enough to burn off the particulates .... I'm now getting 29mpg with it due to the DPF being clogged.

Got the stuff to put in the tank to help but I've also got to get the car up to working temp then drive it at 3000rpm for about 50 miles to "rejuvenate" the DPF