The Royal Opera's Cosi fan tutte is a remarkable production by Jonathan Miller which has acquired a life of its own. On 29 November it was David Syrus's turn to be at the helm, and what a delightful Cosi he gave us, lightfooted and fast, indeed very fast, but the performance gained by this approach as there was never the sensation of hurrying, or of his singers catching their breath. And what a cast! Natale de Carolis offered Mediterranean spice and humour with a good dose of Latin cynicism, whilst earlier in the run, on 26 November, we had seen Thomas Allen's suave Alfonso, devoid of any humanity, a dangerous misanthrope. Colin Davis's tempi were more sedate, and he lingered here and …