I am happy to wait a couple more days for a response if possible. Thanks :-)
Thank you for your message. The error code that is coming up is: EGR:005C Low Boost Pressure. My mechanic tells me that this is a fairly generic code and could be a number of things and he hasn't managed to find an EGR valve anywhere. I have found that if I rev the engine hard in 4th and then put it in 5th then I can avoid limp mode and get the van up to 70 but as soon as the revs drop and then re-apply accelerator then it's in limp mode again. I would value your diagnosis on this as it's looking to me like a costly turbo replacement which I would like to avoid if at all possible. Thanks, Rob.
Thanks for your answer. I ended up taking the van directly to Iveco and they found that the Solenoid for the turbo needed replacing so this was the problem after all. thanks again, Rob.