| Name | Character | Episodes |
|---|---|---|
| Hayley Atwell | Caroline Mortimer | 3 |
| Jack Lowden | Robert | 3 |
| Leo Bill | John Howarth | 3 |
| Richard Pepple | Dublin Hilton | 3 |
| Lenny Henry | Godfrey | 3 |
| Jordan Bolger | Nimrod | 3 |
| Sharon Duncan-Brewster | Kitty | 3 |
| Tamara Lawrance | July | 3 |
| Madeleine Mantock | Miss Clara | 3 |
| David Verrey | George Sadler | 3 |
| Doña Croll | July | 3 |
| Lizzie Hopley | Evelyn Sadler | 3 |
| Ayesha Antoine | Molly | 3 |
| Jo Martin | Hannah | 2 |
| Robert Morgan | Clerk | 1 |