Nine days before last Christmas, one of the biggest sales of an Irish family business in recent years was quietly announced on the New York Stock Exchange. Brown & Brown, an insurance giant with a $15.6 billion market capitalisation, disclosed it had acquired O’Leary Insurances, Ireland’s largest independent insurance brokerage. The deal led to feverish speculation in Cork about how much the O’Leary family had made from the sale. The company had been founded in 1961 by Archie O’Leary, a former rugby international, ocean sailor, racehorse owner and insurance broker who passed away five years ago at the age of…