On February 25 this year, just nine hours after the sale of his Communicorp radio group to German conglomerate Bauer Media had been announced, Denis O’Brien was fielding questions from at an online event with students from Trinity College Dublin. The tycoon covered a lot of ground – from Sinn Féin to the HSE, and from social media trolls to how Dublin is a “Zanussi washing machine” for multinational profits. Predictably, however, O’Brien was asked about his exit from Communicorp, the radio station group he founded 32 years before. His response was telling. “I just don’t know whether a 12-year-old…