I've removed this post because I've had some success with the abusive email I'd posted here, having tracked down the sender's ISP and reported him. Since I also now know who he is, and have received three more abusive emails from him - utterly unpublishable, I'm afraid - it might prejudice any chance I have of pursuing this rather sad character if I leave this post here.
Pity. I was rather enjoying roasting the idiot in public.
Thanks for all your support!
And do visit Richard Dawkins' excellent site, as I suggested, for a taste of what I've been putting up with for the past day or so.