Maybe the next big royal wedding
Or if for Bea's abdication, they have some kind of dinner for the royals, but haven't heard about one.
Thinking the same about Kate, she hasn't got to wear one since her wedding. Brits have too much nice bling to hide, they should be like the Dutch.
Definitely changing times it seems. Think of all the events Diana and older royals would have worn tiaras, or at least big bling to.