My friend just sent me this

"There was an old well dressed guy following me up the hill just now, and he was faster than me, and I reached a point in the zig-zag and turned and he should have been about to pass me but he was just gone. There was literally nowhere he could have gone, and older people in suits don't tend to dash into the bushes anyway. I'm mildly freaking out."

EDIT: Here's a pic of the section of path that he just disappeared into http://imgur.com/k5uoQ6S