Thanks for your input guys; after 10 years experience of MMI 2G on my 2005 A8, it's frustrating to be a beginner again while I look at 2013/4 A8s
I found the version screen on an A8 in which I had a test drive today, but forget where it was for next time.
For info, think it was:
HN+_EU_AU3G_P0532_?
8R0060884AH ECE 5.13.8
This was an August 2012 car so I think this is probably what was on the car when new ...
Julian