Hi the final update, and a big thanks to you all for your advice, Vulcan Bomber advice was spot on,The 90 degree hose bend from the Turbo to the intercooler had delaminated on the inside wall, a small hole in the outer wall let the air in between the two layers creating a balloon effect blocking off the air flow.That simple but so hard to detect. Bye the way the cost of the little bend £52 Regards Trevor