A relative of mine worked at the Dominion theatre when the hi-tech musical 'Time' was running there. He was hugely relieved when Cliff Richard left and David Cassidy took over, because Cassidy used to treat the backstage crew to drinks and meals on regular occasions. As you've probably guessed, the artist formerly known as Harry Webb did not to this.
Your relative must have been fortunate enough to see Freddie Mercury when he made a surprise appearance once, which sadly turned out to be his final live performance. Did they get to meet Freddie?