Written as a sprawling letter, Martine McDonagh’s Narcissism for Beginners is the story of Sonny Anderson’s quest to unlock some answers to his past while over in the UK touring locations from his favourite movie. Meet Sonny Anderson: budding author, ex-meth-head, neurotic and Shaun of the Dead obsessive. Sonny doesn’t remember his mother because when he was five, his father kidnapped him from…