After Paul McCartney stepped down from the roof of the Apple Corps building at 3 Savile Row on 30 January 1969, having taken part in a truly epochal final live performance by the Beatles, it would be three years and a week before he strode onto a stage again. So where did one of the most famous people in the world choose to end this exile of just over 1,100 days from gigging and six years from touring? It was not at Wembley Stadium, Madison Square Garden or the Budokan.