KLEIN CONSTANTIA Vin de Constance 2008 was one of six superb wines chosen to be served during the state banquet hosted at Buckingham Palace by the Queen of England Elizabeth II for Chinese President Xi Jinping and attended by 150 dignitaries who also included British Prime Minister David Cameron and Prince Andrew. The other wines: Ridgeview Grosvenor Brut 2009 (Bubbly from