Familiarity takes a knock. Colin Lawson begins his opening flourish of the Quintet on (written) C below middle C and not on G as is usually heard, even on a basset clarinet. Why so? Because he’s using the latest reconstruction of the part – by Werner Breig (Breitkopf & Härtel, 2005) – as it might have been written for Anton Stadler’s extended instrument. The autograph is lost, but Breig’s logic is unassailable as the notes now match those of the second flourish an octave higher.

It’s an enlightened beginning to an interpretation of distinction. Mozart’s ‘unplumbed melancholy underlying even his brightest and most vivacious moments’ (WJ Turner) strikes a chord with Lawson and the Revolutionary Drawing Room. He draws from his basset (copy of a period model, as are the other clarinets used here) a woody tone of subtly varied hues, balanced with strings equally sensitive to the composer’s skill in texturing. A transparent fabric, notes leant into rather than forced, and tempi and dynamics graduated to suit the phraseology form a foundation to a recreative process that spreads beyond the printed page.

Are Mozart’s fragments snippets of pieces abandoned because they hadn’t reached the standards he expected of himself? Perhaps; yet these completions may be experienced as intriguing (or contentious) conflations of Mozartian creativity and 20th-century intellect. Probably the most absorbing, and absorbingly played, is Franz Beyer’s realisation of K580b for clarinet in C and basset-horn, though Duncan Druce’s skills at conjecture also grace this work – as well as K516c.