John George Vanderbilt Henry Spencer-Churchill , 11th Duke of Marlborough , JP , DL ( 13 April 1926 -- 16 October 2014 ) , was the son of Lt.-Col .
John George Vanderbilt Henry Spencer-Churchill , 11th Duke of Marlborough , DL , JP ( 13 April 1926 -- 16 October 2014 ) , was a British educator .