By Sam Elliott-Gibbs The Royal Family have secret code names for one another – and a very good reason for using them. The Firm, including the late Queen, King Charles and Camilla, were are known to use pseudonyms for security reasons – but sometimes they’re for a bit of fun, too. They aren’t the only royals to follow that path, and Kate Middleton once accidentally let her one slip out. While Prince William was working as a search and rescue pilot in Wales, Kate once mentioned their “secret” names – and they both have the same initials. When on holiday, Kate and William reportedly use them to k…