After recovering from the backfired hypnosis, I just hire the local wizard's guild to defeat the dementors using some magic or some shit that goes on in the Harry Potter series that I can't be bothered to remember or explain. Now with just you in the way of the throne, I grab a brick and throw it at you. Luckily for you, it misses, but it's enough to scare you off the throne and hide!
Throne get.