BBC2 joins Radio 3 in stereo for a live relay of the first half of this evening's Henry Wood Promenade Concert from tne Koyai Albert Hall , London Mozart Symphony No 31, in D major (Paris) (K 297) Clarinet Concerto in A (K 622) John McCaw (clarinet) New Philharmonia Orchestra leader CARL PINI conductor Riccardo Muti Introduced by MICHAEL BERKELEY Sound VIC GODRICH GEOFFREY KLINTON PARKER , Lighting CLIVE POTTER Director RON ISTED