I would assume that there is probably very little difference in the recommendations for sunglasses between the UK JAA and NZ. I think the reason why aviators are so popular is that, due to the lens size, they do a good job in blocking out any oblique sunlight. When I wear mine, I won't say I am trying to make a fashion statement-but I am simply protecting my eyes!
Good luck in deciding on a pair.
dunelmitepilot