Final reply from Audi…
I suspect the broadcasters tweaked the frequency as Audi are clueless.
Thank you again for contacting Audi UK regarding your experience with your Audi A6 DAB radio.
I have now liaised with our internal Technical Team here at Audi UK, they are unable to confirm why there has been an error with your DAB radio as your vehicle does not have access to over-the-air updates. I am sorry for any disappointment that this may cause.
If I can be of any further assistance, please do not hesitate to contact me on the details below.