The Wise Woman of Worksop - S4.E4

The gang are suffering from insomnia and keeping everybody else awake so Gladys gives them a cure, Sleepy Cake, though it only succeeds in making them look like the Beatles. Gladys says her father knows a cure but he is a prisoner in King John's castle so the merry men set out to rescue him.They get him out, though not only do Marian and Robin get caught in the process but the old boy wants to go back to the castle as he is used to being a prisoner.