Thanks for the responses Richard and JJ20X.
It appears from your answers that I clearly forgot how Local can be interpreted. I personally class the regional and nations stations as Local, my definition being anything that isn't targeted at the whole UK.
So oops, sorry about that!
I'd forgotten about the BBC definition of the word.
So, JJ20X, what I was actually asking, though doing so badly, was would it be practical or desirable to VM to put say, BBC Radio Scotland on the same multiplex as BBC1 Scotland HD?
I'm assuming, given the tiny amount of space radio stations use, they'll just leave it as it is and let everyone get all the BBC regional/nations stations as it isn't worth the hassle.