Motorhome is back now and at another Iveco workshop. We've had a chat and I have informed them that I know about the problem and what causes it. They have said they will contact Iveco once they have inspected it.You also need to read this & ask your dealer why he doesn't know?
https://www.motorhomefun.co.uk/forum/threads/iveco-daily-with-zf-auto-box-you-got-one.188929/
Once its stripped down I'm going to have a close look and will pursue Iveco if they are not forthcoming with some sort of help towards the cost, if its found to be one of the faulty parts