Guest Stars Fiona Dolman as Sarah Barnaby Tamzin Malleson as Dr. Kate Wilding Natalie Mendoza as Sasha Fleetwood James Callis as Toby DeQuetteville James Callis as Julian DeQuetteville Paul Ritter as Harry Fleetwood Raquel Cassidy as Diana DeQuetteville Murray Melvin as Bentham DeQuetteville Kerry Fox as Betty DeQuetteville James Clay as Simon DeQuetteville Louisa Clein as Amanda Harding Eleanor Bron as Izzy DeQuetteville William Gaunt as Ludo DeQuetteville