Re: FKK
I think the "sanctions" in the UK in general are that you're told to put clothes on, unless you're obviously trying to cause offence. Like a lot of things we've got very vaguey laws about nudity, presumably because a) it wouldn't be particularly progressive to start codifying it, and b) most of the UK doesn't have a climate that's particularly suitable for it which means it keeps itself in check naturally (not to mention clothing's arguably most important function of protecting dangly bits from physical damage, trappage etc.).