 :The reply is a bit late now, since the palace now has it's own article, but: the palace is mentioned three times in the article (and also already was at the time you posted here). As Richmond was her personal palace and she lived there for 40 years and the history of the building is closely related to her and has remained basically unchanged since her death. So redirecting to her article made sense as long as this was the article which had the most information on the palace on the English language wikipedia.  