Guys Update - SOLVED!!!!
Thanks to everyone and showing the power of this Forum to solve an issue even a Fiat dealer struggled with (I will be telling them!)
Most Gratitude to Deckchair5 - The Idle Control Valve was the cause - followed the guide on the forum and result! Superpleased! Actually the valve did not seem that dirty but cleaned and WD40'ed - The 1.8 was slightly different as it includes an in-line cir-clip and mesh to prevent anything entering the throttle-body but I feel that actually actuating the Butterfly Valve a few times through its full movement resolved. I think the ECU after having lost its config did not know where the valve was but moving through its full range has restored! Now really smooth and idles perfectly around 800 rpm! Thanks again all....
