Part of the BBC Proms.John Wilson and his orchestral supergroup the Sinfonia of London return to the Proms to perform Rachmaninov’s famous Second Piano Concerto with British pianist Benjamin Grosvenor. The concert opens with Lili Boulanger’s mercurial tone-poem D’un matin de printemps, composed shortly before her tragically early death at the age of only 24. Walton’s First Symphony provides the arresting conclusion: a young man’s musical manifesto, composed between the two World Wars, it’s a white-hot outpouring of personal conflict that resolves (or does it?) into a glowing ceremonial finale.