Guest Stars Bruce MacKinnon as Sir Arthur Conan Doyle Charlotte Ritchie as Herself Catherine Tate as Elsie Wright Mathew Baynton as Antonio Meucci Mathew Horne as Frances Griffiths Anthony Stewart Head as Alexander Graham Bell Nish Kumar as Himself Matthew Steer as Edward Gardner Alexander Kirk as Arthur Wright Tim Key as Thomas Edison Tom Stourton as Thomas Watson Kath Hughes as Polly Wright James Meehan as Theosophist