How Nuno Vasconcelos, now in his fifties, came to quit his life as a banker to run the Quinta da Alcaidaria-Mór, his family’s historic Portuguese manor house near the Holy Shrine of Fátima, belongs in a Peter Mayle novel. In the 1980s, Mayle tapped into a middle-class escapist fantasy of swapping the rat race to restore a farmhouse with a vineyard in the hills of Provence.