emmit: Checked on this one this morning , because I was in the area. It's gone.
I cannot imagine, how a muggle came to find it. The deckboards on the bridge , right over it, were replaced once. Removing the old ones would have left it in plain sight, yet it remained. I don't know what kind of person needed a $2 hide a key that badly. Just meanness, I guess.
Since it hasn't been found in over a year and a half, I'm archiving it.