Hi,
By way of an update to my woes.
Needing a mobile diagnostics since the car is stuck in the drive, we did some research and found John at
ecu-repair
Here is a link to his Google profile should anybody need such a service ...... I highly recommend him (as do others)
https://goo.gl/maps/WfDSMX85MLG2RnqbA
The long and short of the issue was that the battery had a bad connection and a fuse under the dashboard needed replacing. John solved the issue and had the car running in half an hour. In addition to this he had the disagnostic equipment that allowed scanning of the various communication busses and modules (it wasn't SD2/3 but I gather was for Alfa and Fiat diagnostics). You could see every Node on the system and any issues with each node. He has given the car a clean bill of health. The caveat to that is that the head-unit is not working. There is no screen output and no radio or anything from the sound system. We have checked the single 15amp fuse that sits under the connector at the rear of the unit and this is fine. The car is booked in for this to be repaired on 1st August. The car runs fine without this, just no sat-nav or music!
Thanks eveybody for your help towards getting this solved; it's appreciated that people will take the time to try and help.
I will keep you updated with the conclusion when the head-unit is fixed.
Have a good weekend.