 Complete the following phrase:  The group was well-known for their annual champagne duels, involving well-shaken bottles of champagne aimed at each other from 10 paces apart; the winner of the duel is whoever first knocks off the opponents top hat. Each dueller represents a differing view on a subject, and the winners viewpoint would later be adopted as League policy. One such duel on 4 June 1975 between Hamilton and another League member decided the groups position on European Community membership in 