To elaborate a little:
(From their website)
I think for games that have been classified by the BBFC, they have to have the UK releases with the age rating classification. Worth double-checking, but I can't see them taking, say, a Polish version of GTA V, since it probably leaves them open to legal problems.
Nah, I worked in CEX while we stuck 18 stickers on boxes and discs of San Andreas that were imported from France.