Close Jackson Lamb (Gary Oldman) looks around in Slow Horses season 4, episode 5 Thankfully, Rosalind Eleazar is set to reprise her role as Louisa in Slow Horses season 6, which will hopefully see the character return to Slough House in full capacity. She left Slough House after successfully blackmailing Claude for her job back, but the character is set to return in Slow Horses season 6, where the trailer has revealed that she will be on the "kill list" targeting all past and present employees of Slough House.