Guest Stars Mark Bonnar as Piers Christie Davood Ghadami as Ali Kolahi Adam James as Dr. Richard Fell Amanda Drew as DI Reid Lashana Lynch as Shona Benson Freya Parker as Mary Smith Bill Ward as Hearns Bryan Dick as Lucas Ballinger Ashley Chin as Mark Benson Bryony Afferson as Petra Smith Wendy Albiston as Stacey Greggs Alexander Newland as Flynn Deshaun Strong as Darius Benson Sammy Kissin as Ellisabet Vrinska Sean Jackson as Roper Matthew Owens as Firefighter