Emphatic accents contribute towards the Diabelli waltz theme’s ever so slightly slowing down as it progresses, although the first variation’s maestoso march stands out for steady gravitas. Vars 3 and 4, by contrast, are attractively fluid and conversational. Var 5 is not quite a true vivace, yet Leotta’s care with dynamics and tightly coiled rhythms compensate. However, Var 10’s broken chords spring from the starting gate and gather wild dramatic steam. Leotta’s tiny hesitations over Var 13’s subito dynamics soften the music’s angular bite and humour, while Var 15’s accented up-beats prevent the molto scherzando rhythm from taking wing. The driving pulse connecting Vars 16 and 17 sometimes loses steam when Leotta works too hard finding meaningful inflections in the busy right-hand writing, in contrast to his energetic momentum and astute voice leading in Var 19.

Conversely, Leotta’s awkward tempo transitions in Var 21 fail to impart contrasting character to the allegro con brio and meno allegro sections. Like Alfred Brendel, Leotta plays Var 22’s homage to Mozart’s ‘Notte e giorno faticar’ slower than Beethoven’s allegro molto implies. The lightness and suppleness of Var 27’s triplets grow texturally heavier and slower as they unfold. Given some of Leotta’s hauntingly sustained Beethoven sonata slow movements, I’m surprised by his perfunctory, unyielding largo Var 31. Var 32’s fugal strands in close proximity ring out with power and clarity, giving way to a tinkly, heavily accented and graceless Menuetto. Aside from stridency in the loudest moments, the engineering is fine, as are the detailed and informative booklet-notes.