Guest Stars Harry Kirton as Finn Shelby Ian Peck as Curly Jordan Bolger as Isiah Annabelle Wallis as Grace Burgess Kate Phillips as Linda Shelby Billy Marwood as Charles Shelby Tony Pitts as Inspector Moss Wendy Nottingham as Mary Stephanie Hyam as Charlotte Murray Branwell Donaghey as UVF Hardman 1 Brendan Gibson as UVF Hardman / Undercover Officer George Gwyther as Karl Shelby Richard Dillane as General Curran Richard Brake as Anton Kaledin Sara Beasley as Wedding Lady 2 Anna Wilson-Hall as Wedding Lady 1 Timothy Harker as Officer 1 John Purcell as Officer 2