I hate to burst any bubbles, but I don't think they had a serial called "Prison in Space." (There was one called "Wheel in Space.") It's a shame because Wendy Padbury, though neither the brattiest nor most voluptuous of the companions, was certainly as cute as they come. Did she get spanked in another serial?
At the beginning of the last serial with Susan (Carole Ann Ford), the first Doctor (William Hartnell), who was also her grandfather, told her she needed "a jolly good smack-bottom." (I've run across that word before, though I'm not sure of the hyphen.)
Also in one of the serials with Jo (Katy Manning) and the third Doctor (John Pertwee), maybe "Dr. Who and the Silurians," the Doctor is taken prisoner and Jo rescues him. As they're leaving, they spend a moment miming, "After you ... No, after you ... No, after you." Jo eventually goes first, but I got the distinct impression he gives her a smack as she goes through the door.