Puccini used to get famously stroppy if his trinity of short operas, Il Trittico, were not performed as a trio. Last year, the Royal Opera House did him proud, performing all three in one night. The results were incredible: Il Trittico (Il Tabarro, Suor Angelica and Gianni Schicchi) is a bewilderingly rich, disorientatingly beautiful experience, not so much a trilogy as a three-course gourmet meal, in which each course is totally different and utterly delicious. We start with stark tragedy; move on to religious transcendence; and finish with a romp. However, it's not always possible to obey Puccini in everything, and the fact that these three operas are short enough, and strong enough, to stand defiantly alone (cf. the terrifyingly good Il Tabarro at Grimeborn, 2012) makes them the ideal hunting-ground for a young opera company like Giornata, who have picked Puccini's often-neglected personal favourite, Suor Angelica, to perform at St Paul's Church, Covent Garden this October.

It's a satisfyingly un-trendy tale of social exclusion, suffering and spiritual redemption, and it's ideal to perform in a church. There are no male characters, and the plot is pretty much over before the action begins: Suor Angelica is all about aftermath. It also benefits from some of the most lavishly emotional music that Puccini ever wrote, in which eerie religious harmonies vie with the swelling chords of secular emotion.

From the moment that the Princess enters (a majestically statuesque and forbidding Rhonda Browne), Giornata's production really delivers the goods. Anne Marie Sheridan (Suor Angelica) sang her "Senza mamma" aria with real feeling and natural musicality, and "died" with equally passionate, pitiable grace. The final chorus of nuns singing a hymn to the Virgin, doubling as the angels in Angelica's tortured vision, while Angelica herself begs hysterically (in a demanding register) for pity and love from the Eternal Mother, was electrifying – particularly when the organ joined in, with Nick Gale bringing a wealth of depth and colour to the almost unbearably moving harmonies. St Paul's Church is itself a very special place to spend some time: the architecture is beautiful, the interior warm and welcoming, and every inscription breathes Hollywood glamour. So, from the Princess' entry on, this production is a winner, and I left with shivers down my spine and tears in my eyes.

Unfortunately, until that longed-for moment comes, the same cannot quite be said for what leads up to it. Owen Lindsay, in his director's note, explains that he has "deliberately avoided any attempt to impose any superficial context or interpretation... [because] such representation is more likely to deny an audience the final emotional impact of the work. In the end, I can only hope that the results speak for themselves." Well, fine; what the results say to me is that the final impact certainly speaks strongly; but everything leading up to that, which in the original contains much of emotional and psychological interest, is here so stripped out and bare that it is virtually mute. The restricted instrumentation of piano (Michalis Angelakis) and piccolo (Anesha Dexter) is simply not enough to do justice to the richness of Puccini's writing; so much has been lost here that I feel we miss out on the real sound of the opera. The singers try much too hard, at the beginning, to fill the resultant vacuum with their voices, straining and forcing notes.

The stage direction was also too static: a lot of "stand and sing", a bit of overacting at times to compensate, and some fairly blank expressions when not on cue. Stillness can be magnetically powerful on stage, particularly where nuns are involved (cf. Les Carmélites at Grange Park earlier this year), but these nuns were neither still enough to be forbiddingly sacred nor active enough to be engaging. Instead, they jostled with sly or silly expressions like a bunch of sarcastic schoolgirls; having spent half my childhood in a convent school, being a big fan of nuns and no fan of schoolgirls, I felt this was a missed opportunity. Like Victor Hugo's in Les Misérables, Puccini's portrayal of convent life in Suor Angelica is profound, intelligent and surprising – or it would be, if only this part were allowed to "speak" too.

Do go – just don't lose heart in the first half. The second is well, well worth the wait.

Suor Angelica, at St. Paul's ChurchCharlotte Valori reviews Suor Angelica, by Giornata Opera in association with Iris Theatre at St Paul’s Church, Covent Garden3