bilbo baggins
I'm not as clued up as some, but I've been a zapper user for some time :).
I'm pretty sure that zapperplans.com does ship to the UK... on their order page(
http://zapperplans.com/order.html ) it says they will ship out of the US for $2.00 shipping so I'm guessing that includes the UK!
This zapper is powered by a single 9 volt battery, I've never heard of a zapperplans zapper that was powered by mains so I think they all are powered by a 9 volt :).
The Posative effects I've had with this zapper are mostly for colds, coughs, stomache aches, etc. But I've heard of people getting cured of cancer when they were using the zapper(there's a link to it on the main page of zapperplans.com). I'm a relatively healthy person(I don't have any serious diseases that I know of) so I don't use the zapper as much as some, but I still get good effects from it :).
I hope this helps!
bilbo baggins