Hi Nicholas,

A DPF (Diesel Particulate Filter) in any car can get clogged up with soot and particulates and it then effectively causes a semi-blockage in the exhaust system. This can affect engine performance and economy, and of course the effectiveness of the DPF itself as its surfaces are covered. This tends to happen if a diesel car is driven only over short distances at low speeds, as the DPF needs a high flow of hot exhaust gases through it to burn off the desposits on the filter surface. 

Sometimes, if a DPF warning light appears, all that's needed is a continuous drive of 15 minutes or more at high engine speed - for example travelling at 100km/h on a suitable road, but in a lower gear than you might usually choose.