fault with my Twilight Princess file?

I'm worried that there is a glitch in my save file for The Legend of Zelda: Twilight Princess.

In the Hidden Village area I encountered a Howling Stone, so I turned into the wolf, howled the song and was informed that I had to encounter the Hero's Shade character to learn the final special attack.

I was told to go to the northern exit of Castle Town, which leads to Hyrule Castle. However, he doesn't seem to have appeared.

I have checked several game guides (including an official Nintendo guide) and I am looking in the right place, but I cannot find him. The Nintendo guide said that you have to unlock the previous 6 techniques for the 7th to appear, but I have done this too.

I beat the final boss months ago, so I cannot remember EXACTLY what I did on the way to the castle, but as it is a very narrow path I find it difficult to believe that I missed Hero's Shade.

As I am trying collect everything in the game, any help would be appreciated. Do you know of this happening before? Is there anything I have forgotten to do? I have gone back to the Howling Stone and it has been 'deactivated' so I cannot do the howling song again. I have over 60 hrs play so far, so I don't really wish to start again.