Possible Clues:

• The man in the middle is looking out for obscene piece of theatre
• Describes the filthy stuff from The Rose Tattoo investigated by the Guards
• Sounds like production of The Birds at The Abbey is bound to draw whistles
• Treacherous conduct in revolting dramatic work
• Evil or dishonest behaviour
• Dishonest behaviour in dreadful piece of drama
• Dishonest dealing
• Whodunit phrase
• It's off-putting in The Abbey and it's bound to attract the whistles
• Unsporting behaviour