Guest Stars Fiona Dolman as Sarah Barnaby Tamzin Malleson as Dr. Kate Wilding Simon Kunz as Miles Rattigan James Lance as Silas Raven Lia Williams as Maggie Markham Una Stubbs as Audrey Braylesford Kobna Holdbrook-Smith as Rob Mead Ed Birch as Curtis Braylesford Adam Kotz as Nick Summersbee Howard Ward as Niall Colebrooke Georgia Taylor as Bella Summersbee Charlotte Cornwell as Jeannie Summersbee Timothy Watson as Vincent Treaborne Oona Kirsch as Suzie Colebrooke Grant Russell as George Summersbee Liberty Mills as Cecilie Petersen