I just met a guy who makes these, and he has kindly donated a couple to my employers.
They look like excellent bits of kit for twitchers, photographers, etc (I'm going to make off with one of ours for an extended test soon so I will let you know what happens.)
in the meantime if you want more info check out the following links
www.popoutside.com. and
http://www.theparkstrust.com/parks%2...e.asp?ID=34783