A royal warrant is the most coveted stamp of approval a brand could hope for, and Queen Camilla just honored three British labels that are particularly loved by Princess Kate. The Queen has awarded royal warrants to jeweler Kiki McDonough , fashion label Me+Em and handbag designer Anya Hindmarch this week—companies that were widely considered in the running when it comes time for the Princess of Wales to issue her own royal warrants . Kiki McDonough has been a royal favorite since the 1980s when Princess Diana first wore the British jeweler’s pieces, and over her royal career, Princess Kate has worn dozens of McDonough’s colorful gemstone earrings and necklaces. While Queen Camilla isn’t as zealous of a Kiki collector as her stepdaughter-in-law, she’s frequently worn a blue topaz and diamond pendant from the brand.…