These guys have found an interesting way to get your hands on the 3 voltages. Hover your mouse over the diagram on this page and check out the piercing connectors:
http://www.ekmmetering.com/remote-water-and-or-gas-metering-package.html
Is that legal in Europe? It looks a bit scarey. What happens if you change your mind?
Re: Piercing connectors
I think that if you did that upstream of your consumer unit/distribution board, the supply authority would not take kindly to the idea, and there's no point (pun unintended) in doing it downstream.
Plus there would be no protection on the "branch" circuit that was tapped off, so the full let-through energy of the supply authority's fuse would be available to destroy the connectors and anything connected.
I definitely don't want to get my hands on the voltages that way. Scarey isn't the word.