As the apogee of variation sets ripe for instrumental transformation, the Goldbergs rarely seem as absorbingly focused, crafted or quixotic as Dmitry Sitkovetsky’s 1985 arrangement. It is a study which makes significant demands on the players, not least in how to make genuine chamber music with string-lines whose keyboard provenance is often unassailable – however imaginative the arranger.

The Leopolds meet most of the challenges but rather float in and out of the grander scheme, thereby creating a performance of symmetrical, formalised units (all repeats applied). Many of the movements are strikingly effective and yet achieved without a particularly incremental sense of their place within an emotional map; it’s mainly a case of responding afresh to each new “event”. Part of the problem, initially, comes from a too regularly detached style from the violin, for example just too insistent in Var 5, too manipulated in Var 7 and even bullish in Vars 10 and 14.

Overall, the second half is considerably more telling in projecting the wonders of Bach’s music and exploiting where Sitkovetsky’s challenging “études” can take us to unexpected regions. Apart from a somewhat wayward Var 17, there are many successes here. Var 19 is a gloriously languid score with pizzicato and elliptical dialogues, superbly captured here – as, earlier, are the similarly poignant Vars 13 and 15.

The canon at the octave in Var 24 is well judged but the other-worldly glory that is the minore Var 25 is the pick of the crop: spare, internal and quite beguiling from all three players, immediately followed by dazzling virtuosity towards the close. With greater simpatico earlier on (with, say, more of the lightness and atmosphere of Var 28), this could have been a still more ambitious and interesting journey.