Par ARNOLD MALCOLM. Originally commissioned by the BBC and first performed by Phyllis Sellick and Cyril Smith with the BBC Symphony Orchestra conducted by the composer. . . .has an enchantingly gentle Ravelian slow movement, and an outrageously jazzy finale which was encored at its Proms premiere - understandably as it centres on one of Arnold's most infectious tunes. . . Ivan March, Gramophone, D…