I'm not sure specifically which 'dorarhy day true story' you are referring to. There could be many personal or specific stories with this name. It might be something very local, or perhaps a name that is not widely known yet.
Yes, it is. The story reflects real aspects of the English class system and the lives of those in service in grand houses. It draws on historical elements to create a vivid picture of that world. The characters' actions and relationships are modeled on the types of situations that were common during that period in history.