Was Mozart's Posthorn Serenade of 1779 written to satirise the conflict between Mozart and his employer, or as a wistful end-of-term farewell to the students? Nikolaus Harnoncourt prefers the latter idea ("leaving the town as empty as it is nowadays at the end of the Salzburg festival"), and brings out every darker moment of the long work with typically accented forcefulness. The varied wind solos from piccolo to trumpet are wittily characterised. But the knockout here is the "Haffner" Symphony, a totally exuberant account which is cinematic in its focus and intensity, racing to a finale which is wild beyond belief.