Twelve years ago, Garrett Hayes got a lucky break. He was a partner in the London office of the US law firm Paul Hastings when a colleague asked him to step in and attend a meeting in Paris with the family office of a French billionaire. His colleague was going on holiday for two weeks. “I went along in his place to meet NJJ Capital, which is Xavier Niel’s family office, which was buying Monaco Telecom,” Hayes recalled.  Cable & Wireless had already tried to sell Monaco Telecom to a Middle Eastern telecoms company, but the Monaco government had blocked…