Wonder if they'll revive the old pre-war full dress uniform for the wedding. George VI (Duke of York at the time) got married in it , so there's a royal precedent. It looked like this if you've never seen it:
File:AVM Lambe.jpg - Wikipedia, the free encyclopedia
Thought it looked quite smart myself, with the exception of that ridiculous busby thingy. Nearly as bad as those stupid hats they inflict on the bandsmen these days.