Royal fans think they have worked out the reason for a last minute change to the Coronation ceremony's order of service.They're speculating that the Prince and Princess of Wales and their children were late to Saturday's celebration at Westminster Abbey, meaning that they were seated after King Charles and Queen Camilla.The planned order of service issued by Buckingham Palace showed that William and Kate were supposed to arrive and be seated before them. It read: "Their Royal Highnesses The Prince and Princess of Wales, Princess Charlotte of Wales and Prince Louis of Wales arrive at the Great West Door and are conducted to their seats in the Lantern.