The concept was imported into the UK by 2 people who discovered the activity whilst on holiday in France. It seems that Go Ape has been a great success and is now developing at a fast pace on this side of the Channel.
My wife (fiancée at the time) having tested it during The Day I wasn't allowed to gate-crash, organised a trip to Thetford Forest along with colleagues and friends.
Despite my initial fears about the vertigo issue, this problem proved to be unfounded and I have to say I really enjoyed myself. It was actually more technical than I expected (you go quite high and you really don't want to mess-up too much with your carabiners!) but you soon get used to the double "attach-detach" sequence. Was it because of the "made in France" on the pulleys? But even on the highest points, I felt safe and confident.
It would have been a shame not to do it! :-)
Photos and videos: http://www.guillier.org/parties/20071021/