I dont have exacz ideas about that light socket stuff, but our modern light sockets have 2 terminals at the bottom, so only the bulb, not the socket goes hot. Furthermore I never again found anything about that rule, it seems to have disappeared in modern books. And it only matters with fixtures. Every lamp with a plug can be plugged in either way, so the wiring of the socket is quite unimportant.
I know the British plugs, they are huge. I always think of Italian, Swiss or American ones, where especially extension strips are much smaller than here.
