Mrs. Peignoir (Yvonne Gilan) appears in the episode The Wedding Party. She is a wealthy French antique dealer who is in Torquay seeking out valuable antiques to buy and sell. She takes a shine to Basil throughout the episode. When she gets back to the hotel slightly drunk after a night out, she trips over Basil when he is kneeling down trying to pick up her dropped purse. Unfortunately, as she is sitting on him, Alan and Jean, the couple staying at the hotel, walk into the lobby, making it look as though he is in an intimate situation.
Later in the episode, Mrs. Peignoir, who is once again slightly inebriated, flirts with Basil when she learns that his wife is out. Basil, who does not particularly like her much, attempts to ward her off and eventually locks his door. Sybil returns and tries to gain entrance to the bedroom, with Basil, still thinking that it is Mrs. Peignoir, tries to ward her off.