Doctor in the House S04E13 - This Is Your Wife

Bingham and Mary are getting married but Mary is applying for promotion and Lawrence fears she won't get it if it's known she's married, so Duncan tells him to keep the wedding secret and leave it to the last moment. The day arrives and Duncan, who is to be best man, and Lawrence, race through an operation, arousing the suspicions of Paul and Dick, who think Mary is marrying Duncan. The wedding goes ahead but the four doctors get into a scrap and fall into a fountain, which shows up on the wedding photos.