SITTING in the stalls, excited about a night of sublime music ahead, it's very hard to keep your heart from sinking at the announcement of various singers' indispositions and Lemsip dependencies.

We were told that Laura Mitchell (as Fiordiligi) would be replaced by her cover, Lorna Bridge, who was also feeling unwell, but going to sing anyway. Optimism wavered further when the overture opened with a dull thud and the realisation that there isn't much of an acoustic for music in the Perth Theatre.

But, turning expectation on its head in a way that would please Mozart and Da Ponte, and putting the vagaries of touring life aside, this show turns out to be a real delight.

Sung in English with no surtitles, under the baton of James Burton, the cast are on the whole wonderfully clear in their text, communicating with great acting a compelling, entertaining and entirely convincing story.

Designed simply but effectively in period dress, with hints at a bower of Eden in the set, this production is directed by Paul Higgins and designed by Samal Black.

It certainly puts paid to the lie that you need grandiose set design in opera, if your acting and singing tells the story. The four lovers are young, energetic and well-drawn characters, with Paula Sides as Despina displaying the most delicious flexibility of expression in her voice. Her presence on stage is as much of a treat as the chocolate she serves at her entrance, although in Act 2 she was too often lost in the balance to the orchestral winds.

This interpretation of the opera leans towards the comic and gentler aspects of Cosi, with Richard Mosley-Evans a particularly benevolent Don Alfonso, and the boys, sung by Anthony Gregory (Ferrando) and Toby Girling (Guglielmo) larking about in beautiful voice. Kitty Whately is a gorgeous and changeable Dorabella. Cosi needs its darkness though, a theme that is taken rather literally by the lighting design at times.

Musically it is underlined with particular affect by Sides, with a frightening backstory for Despina, and also by Bridge (Fiordiligi), who came into her own with her strong arias in Act 2.

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