So  Prince William has finally done it and popped the question to the lovely Kate Middleton, and Britain, and more specifically, the fashion world, is going to be blessed with a new Princess of style. Kate looked amazing in her tv interview announcing the official engagement. Her blue  Issa dress was a nod to Princess Diana, who famously wore an off the peg blue suit when her engagement to Prince Charles was announced in February 1981. Kate’s blue dress was a perfect match to her sapphire and diamond engagement ring, touchingly the same ring that signified Charles and Diana‘s engagement. Now that we know we have a royal wedding to…