There is a thread here on workarounds for adding metadata where available so you have information on what songs etc are currently playing on Live Radio stations. From that thread it appears the BBC don’t push out the relevant data.
Is that something the BBC could be asked by Roon to provide? I apprecaite entirely this is not Roon’s fault or a Roon issue but it is something that would enhance Roon a lot, so would be great if you could!