I think, as long as the sockets are under the same electric meter, it should work.

These will generally work if the outlets in question are on the same leg, or "phase", of the house's power. I don't really know what home wiring is like in the UK, but here in the States houses commonly have two legs, and the breaker boxes are wired such that every other row of breakers is on the same leg (i.e. rows are alternating legs). Trying to use powerline adapters between different legs will usually provide poor or no connection. There are options for improving that (see "phase coupler"), but I don't have any personal experience with those.