Hi (again) Steve.
In anticipation of needing to find the unit in the car containing the satnav, I poked about in the glove box where the only 'unit' I could find lives (i.e. CD player). Guess what, there are two small ports, and from one a small 'chip' was hanging out. This is just below the CD player disc insert. I looked at it and guessed this could be my satnav 'data medium'. so I pushed it home into it's port, and (low and behold) my satnav is now working again. Amazing!
Unfortunately, I suspect that the cars recent visit to an Audi main dealer was the cause, for some reason (and I am guessing here) they may have 'popped' it out and forgotten to replaced it. Anyway the satnav is working now.
I so appreciate your response(s). It gave me confidence to 'have a go'.
Thank you.
Christine.