Meghan Markle was “banned” from wearing Princess Diana’s jewellery by Prince William, according to a royal commentator. The Duke and Duchess of Sussex tied the knot in May 2018 at St George’s Chapel, and Meghan wore a stunning Givenchy wedding dress. She paired the gown with simple pieces of jewellery, including the Queen Mary Diamond Bandeau Tiara. The Art Deco piece was originally created in 1932, using geometric patterns and symmetry. The tiara had not been seen publicly since it was last worn by Princess Margaret in 1965. Meghan’s vintage Cartier bracelet and diamond stud earrings were car…