To deal with the question asked: -

Until the new law is in force - two all evening. The same two. Toye -v- London Borough of Southwark. Sham is technically correct this is not part of the "ratio decidendi" of a case that creates binding precedent - but unless the landlord want to go to the Court of Appeal and possibly House of Lords, and has the funding to do it, he is in practice lumbered.

The view (the same two all evening) is almost certainly wrong - first it is a noise/disturbance issue and the identity of performers is irrelevant to that, only the number affects it, and second, Human Rights Act (law must be interpreted in accordance with if possible) and the point is freedom of expression. But there is a risk that even if the landlord had the funds and will to fight, the UK courts would STILL get it wrong.