By Pablo Mayo Cerqueiro and Amy-Jo Crowley LONDON (Reuters) – Monument Re’s shareholders have launched a sale process that could see a private equity group take control of the company, three people familiar with the matter told Reuters. U.S. insurer Enstar Group, Monument Re Chairman Jonathan Yates and Caspar Berendsen, former financial services head at private equity firm Cinven, are expected to sell shares to a new majority investor, which will also inject fresh capital into the business, the people, who spoke on condition of anonymity, said. Another shareholder Hannover Re, however, is not …