Mrs. Taylor is an acquaintance of Mrs. Jennings’ who knows a “particular friend” of Miss Grey. Through this connection, Mrs. Taylor has the story about Willoughby and Miss Grey being engaged.
Later on, Mrs. Jennings says that Mrs. Taylor knows a Miss Walker who said that Miss Grey didn’t get along with her guardians, suggesting that Miss Walker may have been the informant in the first case as well.
Given that she's frequently corresponding with Mrs. Jennings while the story's action is occurring in town, she appears to live in London at least some of the year.
