Using Columbus TV as DAB Radio

I've had my 2012 Superb Combi L&K from six months old, the TV facility always struck me as  a nonsense but I did use it now and again for DAB radio. Recently I have got bored with the same old stations on FM and returned to DAB but there are far fewer stations on the car than on my DAB radios in the house, for example no Virgin Radio.

I can't see that software updates would be relevant as surely it's only a retune? I've cleared the saved channels and switched the tuner setting of, restarted the radio, switched them on to no avail.

HELP!