[Stooky Bill]

The first one is the only thing that's keeping it going and that doesn't actually need to have any radio broadcast alongside it. The equivalent French system stopped broadcasting a few years ago but kept the data transmission

Can't help but think if they need to keep the transmitters on air for the data broadcast, they may as well keep the radio station alongside it.

If the transmitter is only transmitting data, and no BBC radio then the BBC won't be paying for it, those whose data it is will be. 

Although I think the power demands of just transmitting the data is a lot less than audio, it's just a carrier, it might also well be that it wouldn't be transmitting 24/7