Unfortunately the interpretation of the Act is ultimately a matter for the courts, not the minister. If a local authority is applying the Act incorrectly then the correct course of action is for the person who is being asked to obtain a licence to challenge it in the courts. Of course, this is unlikely to happen. In the meantime, the wording of the Act is so vague that an authority can make its own interpretation - indeed, it has no other option.

The only other course of action is to draw these situations to the attention of the DCMS in the hope that they will clarify their guidance to cover them. Some hope.

In practice, I note that the licensee of at least one of the pubs you were concerned with did in fact obtain a licence. Is there evidence that the policies of this or other authorities are preventing licences being granted for this type of music and preventing sessions from taking place? I know this was a huge concern while the bill was going through Parliament, but the actual effects since it was past don't appear to have been as bad as originally feared.