When Michael Flatley acquired the Castlehyde House estate in Cork in 2001, rain was free-falling through the hall, there was dry rot upstairs, and a tree was growing out of one wall. The basement had five metres in it. Flatley, who fell for the estate after passing it on his way to view another property, stumped up a cool €3 million for the derelict pile, sited on 150 acres. In the years that followed, Flatley, the Irish-American dancer who made his name with Riverdance and his fortune with Lord of the Dance, ploughed a reported €40 million into restoring Castlehyde,…