Very useful info! Hopefully, I will never need it!Just a quick update. I disconnected the electrical plug on the EGR and tried to start the car and it started ok. I connected it up again and tried to start the car and it didn't start, so I thought this was a good indication the problem was with the EGR valve.
I managed to removed the EGR valve which wasn't as difficult as I had thought or read in previous posts, mine came 'unstuck' with only a small amount of encouragement. The EGR valve wasn't that dirty but still gave it a good clean with WD40, but noticed that the centre shaft was not moving, so worked on that with more WD40 until I could get it moving. Put everything back in the car and the engine started first time. I have taken it for a couple of short drives and everything seems fine.
I am guessing that at some point the centre shaft may get stuck again and I may have the same problems, but at least I know if I disconnect the electrical plug, the engine should run ok and the car will get me home!
Thanks for sharing.