Reviewing the Buxton Festival production of Handel’s Jephtha on theartsdesk a couple of months ago, Philip Radcliffe complained that the director, Frederic Wake-Walker, had done too little to justify the staging of this, the composer’s last oratorio: had made it, that is, too static and unstagey. I wonder what Radcliffe would say about Katie Mitchell’s production for Welsh National Opera, revived this weekend by Robin Tebbutt, and a classic case of a director’s reluctance to allow an essentially statuesque, slow-moving work its natural space and pace.

Pick the right dream, and you just might retrieve a precious memory, even in nightmarish terrain where everyone else has lost theirs. That message seems to have been uncannily prophetic for Bohuslav Martinů, who began work on Julietta in 1936, soon to face the terrifying clean slate of a longer exile from his beloved Czechoslovakia with the onset of the Second World War. The pity and the pain of severance are already there in this seething operatic adaptation of Georges Neveux's crammed-to-bursting dream play.

After the all-singing, all-dancing, all-helicoptering brilliance of Stockhausen Mittwoch aus Licht, the dry routine of an opera in concert didn't seem a very enticing prospect.  That's the problem with this year's Cultural Olympiad. We're becoming very spoilt by it. What should have been a mouth-watering prospect - a fantastic cast performing a great opera - suddenly began to feel run-of-the-mill when compared to the once-in-a-lifetime event that was Mittwoch. But my concerns were short-lived.

Ravel composed only two operas, both one-acters, widely separated in time, superficially very different, but both in a way about the same thing: naughtiness. In L’Heure espagnole (1911), the clockmaker’s wife, Conceptión, entertains a succession of would-be lovers in her husband’s absence. In L’Enfant et les sortilèges (1924), the little boy who won’t do his homework, who smashes the teapot, pulls the cat’s tail and rips the wallpaper, suddenly finds his victims coming to life and scaring him to death.

Not all geese are swans, and not all Handel oratorios are like Messiah – storyless, spiritual, monumental sequences of reflective arias and choruses. By definition, though, they aren’t operas either, and it’s always a calculated risk to put them on the stage, as Iford Arts are doing with Susanna, a quasi-oratorio that Christopher Hogwood has described as “a pastoral opera verging on the comic”.

Last night's concert performance of Berlioz's Les Troyens was not a Prom for the fainthearted. After all, if sitting through a five-hour opera had been a daunting undertaking for the Covent Garden audiences last month - who could also enjoy David McVicar's eye-catching staging - then it was inevitable that anyone seated in the Royal Albert Hall for the visually pared-down version was expecting to feel very culturally virtuous by the end of the night.

Purcell certainly doesn’t make it easy for the champions of English opera. His beloved Dido and Aeneas is barely half an evening’s entertainment, so condensed is its tragedy, and the dense political satire of Dryden’s King Arthur text all but requires translation if it is to make sense to a contemporary audience. And then there’s The Fairy Queen – the gauzy, gorgeous semi-opera whose music is the side-dish to a bastardised 17^th-century take on Shakespeare’s A Midsummer Night’s Dream.

Every production of Wagner’s Ring is a challenge. But to stage it in a smallish converted barn seating 500 with little or no stage machinery, which is what the Longborough Festival plans to do in a year’s time, might strike one as a particularly refined form of lunacy. The omens, nevertheless, could hardly be better. The final wing of the edifice, Götterdämmerung, is complete; and in almost every way it’s a remarkable, memorable achievement, a triumph of sheer enthusiasm and dedication – a rare victory for the fools rushing in ahead of the timid angels.

Appearing at Buxton for the first time, Northern Ireland Opera are ahead of the game in marking next year’s Britten centenary by turning their attention to The Turn of the Screw. It is only their fifth production since the company was formed in 2010, so they are nothing if not adventurous. Being a chamber opera, the Screw suits their modest forces well, as it does the venue of Buxton Opera House. First staged at La Fenice in 1954, the claustrophobic opera benefits from an intimate theatre to make the most of its spookiness.

How silly an armchair looks in the Royal Albert Hall - like a rubber duck floating in the Pacific. Yet how right it was for those behind this excellent semi- staged Proms performance of Debussy's Pelléas et Mélisande to try to recreate a bit of fin-de-siècle intimacy for this most intensely intimate of operas. And how appropriate also for there to be a couch on stage in a work that is, and has always been, a psychoanalyst's dream.