Modern diesel engines don;t perform well on lots of short journeys (and 20 mins at 50mph is a short journey)
Give it a good blast on a motorway or dual carriageway at 60-70mph for 30-40 mins at least and get the DPF regeneration going.
Give it a good blast on a motorway or dual carriageway at 60-70mph for 30-40 mins at least and get the DPF regeneration going.