After using my method to get to the top of the castle, head for the front most part of the castle and run up as high as you can. Now execute a Triple Jump parallel with the wall. On the last part of the jump tweak your jump to the side just enough, and you'll be up on the next section of the castle! Now all you have to do is go to the wall on the left and run up the wall. That's all there is to it! You can also access the hidden entrance to the castle from up here as well.
See a video clip, courtesy of Ben Miller, on how this is done!
Sometime in the future I will put up more hidden pages, depending on the success of this one.