Guest Stars Martin Compston as Marcus Georgina Campbell as Young Serena Sara Powell as Fez Kathy Kiera Clarke as Marlene Nicholas Pinnock as Evan Michael McElhatton as Brian Holli Dempsey as Young Poppy Eleanor Methven as Liz Bryan Dick as Al 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