By Mollie Quirk Prince Harry was “asking for trouble” by talking about Prince William and Princess Catherine’s marriage, a Royal author has said. According to writer and author Robert Hardman, who penned new biography, The Making of a King: King Charles III and the Modern Monarchy, the Sussexes’ comments about the Waleses in their six-part Netflix docuseries and also in Harry’s memoir Spare “bit deep”. “Casting any sort of doubt, I think, on your brother’s choice of wife is clearly asking for trouble,” Hardman has revealed to US news outlet Us Weekly. For all the latest on news, politics, spor…