Guest Stars Martin Compston as Marcus Georgina Campbell as Young Serena Nicholas Pinnock as Evan Michael McElhatton as Brian Sara Powell as Fez Bryan Dick as Al Eleanor Methven as Liz Holli Dempsey as Young Poppy Kathy Kiera Clarke as Marlene Owen Roe as Jim Doña Croll as Rachel Caitriona Ni Mhurchu as Sgt Reynolds Dominique Jackson as Vee Michael Ford-FitzGerald as TV Reporter Mark Huberman as PC Jack Bason Michael James Ford as Detective