Please enlighten me if I am wrong, but Princess Anne is a grandchild of King George VI and Queen Elizabeth, and was not Queen Elizabeth a Queen Consort since she was the wife of a reigning king? Could not an alternative explanation of the "direct manner" relate to the fact that George VI in issuing new letters patent granted Anne the use of the Royal title. Otherwise she would have been known as Lady Anne Mountbatten.
Thus my explanation would go: "directed to the manner born," with no need to invoke a chess piece.