Looks like I was half right. My mechanic thinks the EGR is faulty, this causes more engine breaking or something like that and the car certainly felt like it was doing that. Also had a blown fuse for one of the fans and a couple of other little bits.
I thought about the delete kit but its not this part of the EGR thats faulty so that won't help, looking at a few hundred to replace it, combined with two new wheel bearings, a few other bits and my insurance renewal this month is going to be expensive, I will be lucky to get change out of £1300.