I have smoke tested everything and no sign of a leak. I have also blanked off EGR and still get the the same fault together with an insufficient egr flow code, so I was looking to see if this could be a map / airmass inconsistency hence the original question about a single pipe DPF pressure sensor.
I was wondering if the differential pressure was calculated using either of these sensors.

It looks like I will be removing the manifold to see if the swirl flaps or intake is heavily coked up although I can see the electric actuator working ok and the connecting bar is in place and seems to be working.
The OBD mode 2 operating conditions gives
ECT 81C
Rail Pressure 59290 kpa
Intake Air temp 31C
Calculated Load value 0.0%
Intake manifold absol pressure 110kpa
Eng speed 2448
speed 78km/h

I was expecting to see a higher MAP reading on overrun