Special Guest Stars Ṣọpẹ́ Dìrísù as Sean Donovan Guest Stars Rosalind Eleazar as Louisa Guy Saskia Reeves as Catherine Standish Christopher Chung as Roddy Ho Chris Reilly as Nick Duffy Aimee-Ffion Edwards as Shirley Dander Kadiff Kirwan as Marcus Longridge Freddie Fox as Spider Webb Christopher Coghill as Hobbs Eliot Salt as Sarah Dunn Naomi Wirthner as Molly Doran Sean Gilder as Sam Chapman Co Starring Olwen May as Receptionist at The Park Henry Davis as Louisa's Pickup Thomas Coombes as Impounder El Anthony as John Bailey Rebecca Dyson-Smith as Agent Smith Alexandra D'Sa as Lab Technician Chi Aloysius as Tall Dog Musa Lutfi as Ice Cream Man