Guest Stars Una Stubbs as Mrs. Hudson Louise Brealey as Molly Hooper Zoe Telford as Sarah Paul Chequer as DI Dimmock Al Weaver as Andy Galbraith Gemma Chan as Soo Lin Yao John Macmillan as Community Officer Bertie Carvel as Seb Wilkes Sarah Lam as Opera Singer Daniel Percival as Eddie Van Coon Jack Bence as Raz Philip Benjamin as German Tourist Stefan Pejic as Box Office Manager Gillian Elisa as Surgery Receptionist Jacqui Chan as Shopkeeper Olivia Poulet as Amanda Janice Acquah as Museum Director Howard Coggins as Brian Lukis