THE BEATLES’ HISTORY IS RIDDLED with what ifs. What if Ringo had actually been able to sing? What if George had decided after a weekend’s flirtation to put Indian classical music on the back-burner? And what if, in July 1963, a big, bear-like 28-year-old Elvis addict called Mal Evans hadn’t jacked in his day job as a telephone engineer, with an evening sideline as a nightclub bouncer, to become the Fab Four’s roadie and general factotum?