Artaxerxes, St John's, Smith Square, London

Thomas Augustine Arne never quite made it into the last 100 of the BBC's Great Britons. He shouldn't have been far off. After Purcell and Elgar, who? Arne, arguably.

When the great castrato Tenducci intoned the doomed Arbaces' aria "Why is death?" in Act III of Artaxerxes, he unveiled one of the most fabulous moments in British music since Handel. But who knows that nowadays?

Great credit to the Classical Opera Company under Ian Page to have the oomph to present Artaxerxes in concert at St John's, Smith Square. Arne had two notable bursts of success – in the 1740s (launched by Comus in 1738) and again soon after George III's accession. Artaxerxes (1762) was the first real attempt at Italian opera seria in English. It works.

True, lines such as "Nature's great call that governs all" or the girl asking her lover "Ah, when will your rigour end?" pose the odd dramatic problem. Call it the convention of aria. But I question the wisdom here of dumping the (admittedly missing) recitatives in favour of a linked narration "in an attempt to engage the audience more directly and dynamically in the story's unfolding". Isn't this both patronising and wrong? The recit text is, after all, Metastasio's, and keeps the unfolding "story" in the mouths of the characters themselves. These snippets smacked of an apologia for Classic FM.

Still, when the urbane narrator was Simon Russell Beale, and the verbiage so apt ("Rimenes is putty in his overweening hands"; "Arbaces has single-handedly quelled the rebellion, slain Rimenes and dispersed the rebels"), each phrase burnished like a Macedonian shield-boss (the poor Persians only had wicker ones), one gradually warmed to the format. But prima la musica: happily, the best bits of the music triumphed.

Sadly, until near the end, Emma Bell's Mandane wasn't one of them. This terrific soprano, whose soft coloratura for Arne's celebrated "The soldier tired of war's alarms" took wing, verges on all mannerism. Here she was forever grabbing at high notes (with mundane uniformity) and whacking them out like Isolde. Why? Mandane's words became inaudible; the worst whooshes sounded like a foghorn. Ostensibly brilliant, but actually stultifying. "Ye Gods that torture us so." Quite. Sadly Bell wasn't helped by a flood of horn glitches (Page's strings and woodwind were latterly superb).

Far better the restrained Marie Arnet (a future Glyndebourne Melisande), Andrew Kennedy's beautifully delivered first aria (a model lesson in perfection as the crooked Artabanes) or Christopher Saunders' attractively lucid Rimenes.

But the audience, rightly, went dotty for the characterful young Icelandic-born mezzo Gudrun Olafsdottir, who has just acted everyone off the stage in the Guildhall School's L'Etoile, and who – though the voice has yet to settle, and took a time to warm up in this Artaxerxes (Page tended slightly to overwhelm his singers in mid-register) – had the audience mesmerised with Arbaces' great pair of Act III arias. This was Arne to equal Handel: Olafsdottir is – I hope – on the way to something great.