One miracle of musical performance is that a work you’ve loved for years can be revealed as never before in an outstanding interpretation. That happened to me last week at the New Ross Piano Festival when 22-year-old pianist Magdalene Cho turned us upside down in Bach’s Sixth Partita. It happened again last night when Peter Whelan and his Irish Baroque Orchestra hit 1788 with one of the three symphonic masterpieces Mozart composed in a single summer, the 39th.

35 years ago, persona-now-non-grata John Eliot Gardiner revealed how performances of Mozart’s Idomeneo and La Clemenza di Tito allying period instruments with great voices could electrify in a new way. And here we were last night with Pablo Heras-Casado, a conductor as at home in Wagner at Bayreuth as he clearly is with the Monteverdi Choir and Orchestre Révolutionnaire et Romantique, stunning us with a consistently vigilant and alive Mozart Requiem.

One door closes, and another one opens. A lot. It’s extraordinary what value those two simple additions to the Royal Albert Hall stage lent to Glyndebourne’s performance of The Marriage of Figaro at the Proms.

Over 100 years ago, John Christie envisaged Wagner’s Parsifal with limited forces in the Organ Room at Glyndebourne. He would have been amazed to see it arrive on the main stage this year. But émigrés Carl Ebert and Fritz Busch persuaded him that Mozart was the real country-house ideal. Le nozze di Figaro remains Glyndebourne’s perfect opera, and Mariame Clément’s new production, launched last night with the 588th performance here, keeps it real.

Marianne Moore once famously defined poems as “imaginary gardens with real toads in them”. Operas also fill, or anyway should fill, their artificial horticulture with genuine beasts – and flowers. And no work demands the population of a fanciful landscape with authentic passion more urgently than Così fan tutte. Mozart transforms this shabby little shocker of a plot – as the meddling know-all Don Alfonso “tests” the two sisters’ fidelity to their sweethearts – into a vehicle for music of exquisite truthfulness that grows from a bed of fraud and lies.

“It is so disgraceful, what happened there,” says Anita Lasker-Wallfisch, in a comment that is the understatement of the century. She is referring to the genocide perpetrated by the Nazis in concentration camps like Auschwitz-Birkenau, where she was held prisoner.

Just now, the notion of a long-term project that concludes in 2041 sounds like an optimistic bet on the far future worthy of some 18th-century Enlightenment philosophe – Voltaire’s Dr Pangloss, maybe. The musicians of The Mozartists are clearly hoping for the best in the best of all possible worlds, as their MOZART250 programme ambitiously tracks, in annual increments, the music that Wolfgang Amadeus wrote exactly 250 years ago.

Donizetti: Songs Vols. 3 & 4 Michael Spyres (tenor), Carlo Rizzi (piano) – Vol. 3, Marie-Nicole Lemieux (mezzo-soprano), Giulio Zappa (piano) – Vol. 4. (Opera Rara)

Tamino in the operating theatre hallucinating serpents? Sarastro’s acolytes wheeling lit-up plasma packs? From the central part of the Overture onwards – just when we thought we'd escape directorial intervention in Olivia Clarke’s racy conducting - Jamie Manton’s production of Mozart's adult fairy-tale looks distinctly unpromising. But by Act Two, it becomes one of the most moving Magic Flutes I’ve ever seen. Glorious singing and youthful energy help to make it so.

Drained as they are at present of crucial funds, WNO are managing to put on only two operas this spring, and spaced out to the point where it could hardly be called a season. For their new Peter Grimes we must wait till April. Meanwhile we can relish Tobias Richter’s sparkling nine-year-old Figaro, skilfully revived, with a few tweaks, by Max Hoehn.