MEGHAN Markle and Prince Harry’s baby may not be called Royal Highness – thanks to its great-great-grandparent. King George V introduced a rule in 1917 which means their baby will need special permission from the Queen to become a HRH. Only the eldest son of the Queen’s first born, Prince Charles, is entitled to be a HRH, no younger sons or daughters. The Letters Patent is a method that allows the sovereign to give orders without involving Parliament. Although the Queen is yet to make special permission for Harry and Meghan’s first child to be a HRH. As it stands, a son will receive the title Duke – and if Meghan Markle and the Duke of Sussex have a daughter next spring, she will not inherit ANY title. It comes after circulating rumours claim Meghan will not have her baby where Kate had her three children. The Duchess of Sussex is said to be eyeing up the maternity unit at Frimley Park Hospital for the birth of her and Prince Harry’s first child. Kate, the Duchess of Cambridge, had Prince George, 5, Princess Charlotte, 3, and eight-month-old Prince Louis at the Lindo Wing of St Mary’s Hospital in Paddington, West…