Guest Stars Richard Durden as Conor Hodgson Daniel Weyman as Max Thorndyke Julia Haworth as Rosie Chamberlain William Ash as Major Mark Sealy Ben Bailey Smith as Lieutenant Colonel Ben Carmichael Graham Turner as Arthur Simpson Clare Higgins as Professor Katherine Dukes Tina Chiang as Simone Taylor Ash Tandon as DI Karl Guyatt Will Stevens as Private John Sealy Caroline Lee-Johnson as Sandra Gibbs Michael Simkins as AC Harry Lennox Daniel Parr as Edmund 'Fish' Fishbourne