Nice one for posting this...makes me think how motorway is not always good as the 6th gear leaves the revs too low. Hopefully the new CR engines do a better job of clearing the soot or simply dont produce as much as the PD engines! :confused:
 
Regeneration starts at 2200 rpm and needs to be above 50 kmh. IIRC over 3500rpm and the system (on the PD) deactivates.

CR regeneration is a lot more effective, thats due to the better electronic control where as PD relys on the camshaft for injector operation which makes a post combustion cycle very difficult.