Just for a bit of further info Carl. The damage has probably already been done and the chances are that it will come back again with more carbon on the egr. The last one I did which was under similar circumstances came back after about 6 months so I just cleaned the egr again, changed the oil and filter again and then cleared the codes. That vehicle had also been used for doing the school run (about a 5 minute walk!). The customer then decided to pass the problem on to someone else.
Regards, Bryan.