Lyle,
All 3-pin British Standard plugs are polarized, whether BS1363 or BS546. French grounding-type plugs are also polarized, whereas the more common European Shuko and the two-prong flat "Euro" plugs are not.
I've seen various types of "ceiling rose" plugs, and they certainly make installing pendant sets easier, although you're still left with working above your head for the wiring into the outlet.
