Ah, yes I have just found that, there was a link to it. What's the point of calling it something else?
Evening wear - Black tie
Our Gala Evenings, Celebration Night or Black Tie nights, offer a chance to get dressed to the nines in glamorous evening wear. Don your favourite cocktail dress, tuxedo, ball gown or dinner jacket, or alternatively a dark business suit and tie. You may also wear formal national dress or military uniform.