The stand-off continued for over 20 years, but it ended in a win-win. Last March, the bloodstock billionaire John Magnier sold Portrait of Omai, a life-sized masterpiece by the British painter Sir Joshua Reynolds, to the UK’s National Portrait Gallery and the Getty Museum for £50 million. He had bought it in 2001 for £10 million. Quite the return. On the other hand, the Irish tycoon never got to enjoy Omai at his stud in Coolmore. An application by his legal representatives for an export licence to take Omai out of Britain in 2002 was ultimately refused. Under UK law, the government has considerable powers…