Shirley Eaton portrayed a character, Dorothy Denton, who had a last name that rhymed with her own. Jill Ireland played a character, Jill Thompson, who had the same first name as her own.
When the nurse is discovered hidden in the bed, she runs up the stairs in her underwear - but when she next appears both her petticoat and hairstyle are different.
When the nurse who was left tied up in a bed is set free by a colleague we see that her hands were tied but not her feet: she would have been able to get up and walk at any time.