Beethoven's Fifth Piano Concerto is sometimes called the "Emperor's Concerto". And worthy of an emperor is the programme of this summer festival, as always with conductor Yannick Nézet-Séguin, who this time will conduct the London Philharmonic Orchestra and the Chamber Orchestra of Europe. The goddess who leans towards the emperor is, as so often with Yannick, the magnificent Joyce DiDonato, who can do everything vocally and stylistically - this time Berlioz, Mahler and Brahms. In between, a man whose piano tone shines like mother-of-pearl: the South Korean pianist Seong-Jin Cho.