The person hasn't done any caching since 26th July, though as you say he's still visiting gc.com, so it could be a temporary break. But if he won't respond to email that doesn't look very good.
You could try posting in the Groundspeak UK forum too. I don't see any reason why you shouldn't name the cacher - after all you have tried to contact him and got no response. If you name him someone may draw the post to his attention if he doesn't see it himself.
Other than that I don't know what you could try.
(Edit: I said the link wasn't working, but it is now.)
Do not go gentle into that good night.
Rage, rage against the dying of the light. (Dylan Thomas)