In this episode of Channel 4's backstage documentary The Sound of Musicals (the second of four), we followed the fortunes of two producers at very different stages in their respective careers.

Theatre impresario Sir Cameron Mackintosh is the man behinds a string of hits including Les Misérables, The Phantom of the Opera and Cats. The director on his latest show, Barnum, describes him as "hands-on" which, judging by the tense discussions last night, is theatre-speak for "interfering busybody with a million impractical ideas".

Meanwhile, actress-turned-first-time producer Amy Anzel was struggling to find any director at all, even an unhappy one. After Strictly judge Craig Revel Horwood pulled out of directing her stage version of Fifties-set sitcom Happy Days, she was reduced to ambushing original Fonz actor Henry Winkler at a book signing: "It's 'Sad Days' at the moment."

There was one lighter moment, with a scene revealing how Mamma Mia! achieves that year-round glow: "It's all in a gay's work, my love!" said make-up artist Rick merrily as he watched his assistant Henrik fake-tanning a production line of young men, all of them nude, save for a strategically placed sock. There should have been more. Instead, The Sound of Musicals featured too much of the grinding gears and the sweaty rehearsals and not enough of the exuberance that makes West End musicals so popular. If there's really no business like show business, why is The Sound of Musicals such a drag to watch?