Well, I've just got back in from refitting the EGR and a test run....\
On first start She chucked out a load of smoke, but that soon cleared and the car is now beautiful to drive, brought a tear to the eye. It actually responds in low revs, and I had no random power loss.
I won't get too excited yet as it had a period of about 3 days recent where the problems were non existent but it does feel a lot nicer on the road this time!
On the subject of blanking, I noticed the blanks etc are cheap enough - I will probably go for the restricted plates so as to not set off the dash light. If this light does appear however, I'm guessing removing the blanks removes the light again?