The juddering was getting prgoressively worse mainly cold starts have with higher than normal revs between 800-1200RPM and generally running rough for the first 10 minutes each morning, rescanned and found the P2453 and P0471 faults again but every time i cleared these they reappeared. Quick scan of the internet would suggest the Exhaust pressure sensor is the likely cause of the problem and as it is considerably cheaper than a new DPF it seemed like a good place to start.
The sensor is located on the rear left corner on the BMN engine, removal is pretty each as it is only secured by one bolt and the two vacuum pipes are held in place using the squeeze type clamps.
As the loom runs across the back of the block and is above the turbo i checked the wiring for and breaks or heat damage and was surprised to find that not only had the plastic ducting melted but so had the insulation on three of the wires which were also broken. The three were resoldered (only two shown) then wrapped in TESA tape as i don't have any shrink wrap to hand.
Rescanned and the fault codes have gone so hopefully it was a combination of degraded wiring and the sensor but i will not know until tomorrow morning :)