Guest Stars Adeel Akhtar as Inspector Lestrade Susie Wokoma as Edith Grayston Fiona Shaw as Miss Harrison Burn Gorman as Linthorn Ellie Haddington as Miss Gregory Frances de la Tour as The Dowager David Bamber as Sir Whimbrel Tewkesbury Hattie Morahan as Lady Tewkesbury Claire Rushbrook as Mrs. Lane
