All the filters were changed Matt. Performance is fine once the engine is warm and to temperature, that is the annoying thing. The diesel chatter seems to be a bit excessive when cold as well, any views on this being a contributing factor? Using good quality diesel, used Wynns fuel clean with EGR cleaning additive and Wynns valve and uplifter additive. No change when cold.
I will relay this information to my garage about the EGR THEORY. Any other advise you can offer?