If you didn’t know better, you’d think Welsh National Opera was embarrassed by bel canto . No form of opera rejoices more openly in melodramatic plots, theatrical excess and the untrammelled glory of the human voice. Yet WNO set its 2013 Donizetti Tudor trilogy in a grim black box, and now Annilese Miskimmon relocates Bellini’s I Puritani amidst the khaki paint and plastic bucket-chairs of a 1970s Ulster church hall, rendered with depressing accuracy by designer Leslie Travers.

To be fair, that’s just the starting point. Miskimmon’s conceit is that the original 17 century drama is playing out in the mind of the unbalanced heroine Elvira. So while a silent figure representing the real Elvira clung saucer-eyed to the wall, the stage filled with stovepipe hats and starched ruffs: this I Puritani certainly didn’t lack Puritans. Confusing, but it just about worked - at least until a vicious last-minute directorial intervention which undermined the logic of the drama and soured Bellini’s music.

But what music! Linda Richardson as Elvira, Wojtek Gierlach as Giorgio and David Kempster as Riccardo were all magnificently, sonorously on top of everything Bellini threw at them. Richardson, in particular, conveyed both eerie fragility and inner steel in her extended mad scenes. As Arturo, Alessandro Luciano stood in for an indisposed Barry Banks with a sweet tone and some blood-curdling high notes.

Conductor Carlo Rizzi swept it all along to the manner born. Bellini’s score is Romantic with a capital R, glowing with orchestral colours and some tremendous choral writing, tremendously delivered by a WNO Chorus that can phrase as subtly as it can act. But it was the WNO Orchestra that emerged as the surprise star of the evening. All this bel canto has clearly rubbed off: it’s quite something to hear an orchestral violin section that can almost out-sing a cast like this.