Arthur Crowe is a non-canonical character, created for the 2022 miniseries Why Didn't They Ask Evans?, an adaptation of the Agatha Christie novel of the same name. He is the driver to Lord and Lady Marcham.
He is employed by Frankie to drive her around Marchbolt, which is later characterized by Lady Marcham as unauthorized stealing of domestic staff. After Bobby's poisoning, Arthur impudently watches Frankie in the rear-view mirror as she is changing from Bobby's clothes, which earns him a reprimand.
When Frankie goes to interview Ted Miller at the carnival, Arthur gets his uniform splashed with mud and it has to be sent to the dry-cleaners. This later gives Frankie the idea to seize the uniform and give it to Bobby who can pretend to be her driver at Merroway Court.