[Salop67]

Got a new 530 d which I am delighted with except for one thing.
I have just returned from a 100 mile round trip and on reaching home and turning off the engine the cooling fans were running and I could smell that a forced regeneration was going on.
My understanding is that the dpf cleans itself when running at high speed(motorway) and it is only when the dpf becomes blocked after a lot of short journeys that extra fuel is injected into the dpf and a forced regeneration occurs.
Why would the car start a forced regeneration towards the end of a lengthy and mostly fast(over 60 mph) journey?
I thought it would be useful to ask on here before a trip to the dealer. I guess they will tell me there is nothing wrong with it.