Anna Maxwell Martin Agatha Christie Actor David Avery Freddie Mercury Actor Isy Suttie Jean Sexton Actor Steve Pemberton Bill Grundy Actor Bill Paterson Sir Arthur Conan Doyle Actor Alex Pettyfer Actor Toby Williams Mike Actor Rosie Cavaliero Dorothy L Sayers Actor Kieran Hodgson Malcolm McLaren Actor Seb Cardinal Ric Parfitt Actor Mark Bonnar Billy Actor Paul Kaye Actor Frankie Fox Johnny Rotten Actor Felicity Montagu Actor Adrian Scarborough Chief Inspector Danders Actor Alex Beckett J-J Actor Nick Mohammed Horace Lambardi Actor Con O'Neill Tony Actor David Boyle Journalist Actor Hugh Coles PC Horley Actor Freddy Syborn Writer Guillem Morales Director John Hardwick Director Ben Palmer Director Frank Skinner Writer Neil Forsyth Writer Simon Delaney Director Jim O'Hanlon Director Paul Doolan Writer Ed Dyson Writer Morwenna Gordon Executive Producer Matthew Mulot Producer Abigail Wilson Writer Jane Bell Producer Tilusha Ghelani Executive Producer Amanda Spencer Producer Jon Mountague Executive Producer Tim Allsop Executive Producer Zoë Rocha Producer John Rushton Producer