I did find the problem to be a split in the pipe, just used some duct tape on it for now, but the smoke has cleared. Forgot to put the small vacuum tube back on, so the engine light came on, code reader off ebay for £13 and fixed that too.
Im sure I have seen this on here before but search won't allow 3 letter words. I am getting embarased by the amount of black smoke being thrown out, and believe I may need to clear the valve. There is also an occasional hestitancy when cruising. I have changed the air filter but that has had little benefit. Can anyone tell me where this valve is, how hard is it to clean and if I need anything in the way of gaskets etc. It is a 2.0d, with 75k. Thanks