More generally re accents I think even within Scotland regional accents, never mind the dialects themselves, are pretty much ignored in drama. Even in the "Shetland" drama series the only local accent seems to be the policeman Sandy and everyone else sounds as if they come from the central belt. And the actor who plays Sandy is himself a Shetlander. So no real attempts for actors to try a local accent. I've never heard anyone in any drama with a Borders accent.