Two rules should help the non-Donizettian: avoid all stagings of the prolific Bergamasco's nearly 70 operas other than the comedies; and seek the guarantee of top bel canto stylists. Conductor Mark Elder and soprano Joyce El-Khoury certainly fit that bill, and a straight concert performance of L'Ange de Nisida, given at the Royal Opera in association with Opera Rara, got it exactly right.

Alzira is Verdi’s shortest opera and his least performed, and you have to ask why.

Remastered they may be, but the 20 live operas recorded here between 1949 and 1964 vary soundwise from clean at best to atrocious, with all the caprices of stage noise and audience participation seemingly acceptable at the time (so often there's the shouting prompter who seems duty bound to cue everything – even interjecting a loud libiamo! in the silence before the voices kick in for La traviata's Brindisi).

Katie Mitchell’s production of Lucia di Lammermoor opened at Covent Garden in 2016 and now returns for a first revival. Royal Opera were clearly expecting great things, even from the start, and this is the third cast to have presented the show, after two separately cast runs last year, and a commercial DVD is also available. Mitchell has repaid their confidence with an impressively conceived production: visually arresting, suitably dramatic and with many subtle narrative additions.

It should have been unmodified rapture: a gathering of English National Opera team members old and new celebrating the doyen of the company's best-selling productions. And, as has always happened with the artistic side of the company, this loving homage to Sir Jonathan Miller sounds like a triumph. Critics weren't invited to the gala - statement, not sour grapes; this was a charity event, after all - and the final rehearsal was closed, though not apparently at the wish of anyone performing. The circumstances, though, tell us a lot about a company divided.

Given the horrors lurking in the composer’s more familiar operas, the warning that Maria de Rudenz is “perhaps the darkest of Donizetti’s tragedies” carries no little weight. A Gothic spectacular with echoes of The Castle of Otranto and Matthew Lewis’s The Monk, Maria’s dramatic excess is tempered by a fine score, full of atmospheric chorus writing and some particularly lovely arias for baritone.

The curtain is up for the overture to English Touring Opera’s new production of Don Giovanni, but no-one is on stage. Instead, we gaze at Anna Fleischle’s set: a creation in two layers. On the top, elegant Klimt panels glint with gold. Below, and joined to the opulence above by a rickety looking metal fire escape, is a Piranesi-like underworld of drab brick, archways and mysteriously curving passages – perfect for lurking or throwing sinister shadows.

Lucia di Lammermoor is an opera in which men spend an awful lot of time talking about women, and very little actually talking to them. (Which, if nothing else, ensures a rather more dramatic denouement than a frank conversation about everyone’s hopes and dreams would produce.) Enter director Katie Mitchell and her “strong feminist agenda”, determined to give Donizetti’s women back their voices, and with them the agency every plot twist in the opera conspires to deny.

Sunlight bounces off Derbyshire stone, buskers strum on the Pavilion Gardens bandstand and there’s improvised Shakespeare on the streets: it’s Festival time again in Buxton. Frank Matcham’s Opera House doesn’t present a particularly festive appearance to the street – he had to squeeze it in next to the Winter Gardens, after all – but once you’re inside, it’s a positive confectioner’s shop of ceramic tiles, coloured glass and swirling gilt, quite as breezily ritzy as any of Matcham’s West End creations.

Fashion is a funny thing, in opera no less than the sartorial trappings that go with it (everything from tight, hipster trews to billowing ballgowns at last night's Glyndebourne season opening, in case you were wondering). Donizetti's classical tragedy Poliuto is historically a miss rather than a hit, never quite finding its footing in the repertoire, despite some early success.