Doctor in the House S06E10 - Physician Heal Thyself

Whilst Dick beats the captain at cards, Duncan has a day on the beach with the charming Rosita, only to find himself in extreme agony, clutching his side. He is sure he has appendicitis but, now the Begonia has sailed, there is only one other person on board - discounting the vet - who can operate - Dick Stuart-Clark. Duncan is most reluctant to let his friend loose on him though fortunately it transpires that his affliction is food poisoning from the ice cream he ate on the beach.