Guest Stars Daniel Adegboyega as Pierre Martineau Adam Isla O'Brien as Ryan Henshall Barry John Kinsella as Michael Whithall Keith McErlean as Albie Garston Sophie Mensah as Cheryl Lee Cal O'Driscoll as Ollie Holly Sturton as Beatrice Garston Charlie Geany as Young Daniel age 12 Chris Newman as Remy Danielle Ryan as Ana Dao Darcey Campion as Harper age 13 Helen Norton as Mary Ann Bolt Ciara Kelly as Sarah age 13 Áine Hayden as Serafina Paul Elliott as Unit Commander