[Rodge]

Thanks to everyone for their posts. I think a lot has to do with where in the exhaust system the DPF is located, the closer to the engine where its hotter, generally the better. My diesel had its DPF about three quarters of the way down its exhaust system. Another thing is that its quite likely manufacturers are now designing DPF's that are more user firendly, (easier to achieve effective regeneration across a broader spectrum of operating conditions), than they used to be.