Lost autographs raise theories. Back in 1948, George Dazeley surmised that Mozart’s Clarinet Concerto and Quintet, composed for Anton Stadler, were written for an instrument of extended compass. Dazeley’s hypothesis was accurate; today we know that Stadler exclusively owned a clarinet that went a third lower than any other. And an unknown hand transposed Mozart’s notes within that interval to fit the range of a conventional instrument. But the decisions on restoring them to Stadler’s equivalent – the basset clarinet – rest on conjecture. In this respect, Nicholas Carpenter goes further than Nicola Boud but her judgement is just as valid.

She is in full command of a modern copy of an attractively woody-toned period instrument; but her matter-of-fact response to the music is perplexing. Boud’s dynamic spectrum is narrow and her phrasing tends towards bluntness, except in Variation 5 (Adagio) of the last movement which evokes finer feelings. The Edding Quartet self-effacingly match her approach, generally muting their own contribution.

No muting in the D minor Quartet. The Edding offer a wide-ranging interpretation that plumbs the aspects of its seriousness and melancholy. Tempi are sensitively selected and all repeats are observed, as are dynamic markings including a quiet sotto voce at the beginning. The switch from swift, severe Minuet to the brighter moment of a liltingly courtly Trio exemplifies their grasp of shifting atmospheres. The recorded balance is superior to that of the Quintet where the soloist is too forward and the strings closed in.