Here are 2x links that will explain all. As for the succession of Her Majesty by the next Monarch and what they use for their Royal Cypher; that will be up to them.
Crowns & Cyphers as used on badges & medals
https://www.postalmuseum.org/blog/ro...SAAEgIEl_D_BwE
Plus horror of horrors, this thread uses the dreaded “B-Word”. Just for the removal of all doubt, a Brevet is a certificate and a flying badge is a badge - or sometime commonly called your wings. You should get a certificate along with your wings at your presentation ceremony, the certificate is your brevet and the badge/wings is your flying badge.
Page 103 of the following link refers:
https://www.rafmuseum.org.uk/documen...Journal-52.pdf