‘Zacs for Macs” read the advert on the side of Oxford buses in the 1950s and 60s, in the days when ‘mac’ meant raincoat, not computer. The Cornmarket Street shop could well have sold the macs worn by Guglielmo and Ferrando in Longborough Festival Opera’s new production of Così fan Tutte. When their fiancées Fiordiligi and Dorabella last saw them, Guglielmo and Ferrando were nattily turned out as naval ratings, setting out for war. But now they have returned wearing macs, and disguised as — I’m not quite sure what, doorstep insurance premium collectors perhaps.

Anyway, the ruse works, as the two men set about testing their girls’ fidelity — in this production the disguises are stripped off when the men think the girls aren’t looking. This saucy touch adds a nice frisson to the situation: will they get caught out?

Throughout, director Jenny Miller reckons that Mozart and his librettist da Ponte need no embellishment — in contrast, incidentally, to the new Welsh National Opera production of Così, which is also set in a 1950s seaside town: WNO adds a number of extra characters and complicated visual distractions to the plot. At Longborough, the fact that this is a matter between two couples is emphasised from the start: as the curtain rises, Guglielmo and Ferrando are ensconced with their fiancées in the back row of the local cinema — double, “lovers’” seats, of course. The film finishes, but the cinema screen cleverly remains in use, for the projection of backdrops and large surtitles (designer Jane Bruce).

Elizabeth Donovan (Fiordiligi) and Louise Callinan (Dorabella) have both sung in Così before, and they give assured performances, making it clear that Fiordiligi is much less willing then Dorabella to melt into the arms of a new lover. As Guglielmo and Ferrando, Rodney Clarke and Nicholas Watts are making their role debuts. On opening night, they seemed a spot uncomfortable vocally at times, but Clarke nonetheless projected a Guglielmo who enjoys life, while Watts’s Ferrando is plainly aware of the pain his behaviour could cause — his aria Un’aura amorosa was a high spot of the evening. Meanwhile, Sasa Cano dispenses a seedy cynicism as Don Alfonso, and Martene Grimson is a sassy, bare-midriffed Despina.

In the pit, Gianluca Marcianò and his lightly textured, responsive orchestra are ideal accompanists in a production that sees Così primarily as a comedy. Only at the end did things seem a bit unfocused, and hustled through. But that may well sort itself out as the run progresses.

For details of the Longborough Festival Opera season, and ticket availability visit the website (www.lfo.org.uk).