Please do stu. Technical posts are by far the best to read.
I'm sure lots of people on here drive diseasels and I for one would like to be educated on them.
I also hate smoke so will keep the dpf fitted.

When I bought my car after a couple of weeks the dpf light came on, turns out the throttle valve didn't work (common prob) and the egr stat was stuck open so it wouldn't get over 70*
So it missed the last 2 regens.
Changed both of those and it did a regen straight away and now runs much better.