Thanks for the suggestions folks.
Trebor1652: I don't see any little ladder symbol, so either we have different radios or I'm looking at a different screen to you.
Vateriel: that seems to be it. There's no obvious button on the screen, but I discovered that by randomly tapping there are certain places that toggle the display between the pre-set list and the station actually playing. Thanks for that.
RDS traffic info: after some googling, it looks like DAB does not actually carry traffic info in the same way that FM does. Some people report that they do get traffic interruptions when they listen to DAB, but this may be caused by the last TP FM station they listened to still being on in the background, so when that gets a traffic announcement it breaks into the DAB broadcast. I think. I thought DAB was supposed to be the future, but this seems to be going backwards.