As you already know I believe that Jack the Ripper planned the murder of Mary Kelly to spoil Lord Mayor´s Day.
I have also stated that I think he posed the dead body the way he did to confirm to the police that he was the murderer (since he was planning to do extensive mutilations on the victim and knew that the police afterwards could have doubts about who the killer was).
I have also told you about a letter I think he wrote in the press, giving the adress to Miller´s Court and the name of the victim: Mary.
In this letter he hints at Lord Tennyson. Lord Tennyson wrote a play called "Queen Mary". Lord Mayor was in it to.
The play was performed in London.