Possible Clues:

• It follows the sound of the quartet at that point
• 'Where, by the sound of it, they're a quartet, it follows (9)'
• Consequently European umpire gets involved in other foul
• So not here, for the end of June
• So three got off with a warning
• So locked in combat here, forever
• Start of a conclusion
• So get three of, all different, again
• Reference in logically proved proposition, mostly?
• So there! Something Norman shouted?