Apple-cured salmon at the Rex WhistlerPhotography by Neil WissinkWhat could be more civilised than a good meal and a glass of wine after touring a museum or gallery? Already elevated by the exposure to art or historical objects, dining out offers the opportunity to rest and reflect. Until now however, the in-house pickings at most institutions have been just that: institutional. With notable exceptions – the Continental-style brasserie at the National Portrait Gallery, the co...