Hänsel und Gretel, Holland Park, LondonEliogabalo, Grange Park, HampshireRoberto Devereux, Holland Park, London

Packing the kids off to the woods for berries makes sense in Holland Park's wartime opera fairytale

Bacon, butter, eggs and beans. Flour, sausages and onions. Simple pleasures for most of us but paradise for Getrud and Peter, the hard-pressed parents in Stephen Barlow's Second World War staging of Hänsel und Gretel for Opera Holland Park.

After English National Opera's VE-Day Peter Grimes and Glyndebourne's post-war Falstaff, we should be used to ration books and utility suits, carefully darned stockings and stiff upper lips. But Barlow's 1940s fantasy is the first to open with the wail of an all-clear siren and two little gas masks, and the first of the recent wave of Hänsel und Gretels to present this darkest of fairytales from a child's perspective.

Paul Edwards's monochrome set designs are dominated by a vast four-panelled door. The handle is above head height, the skirting-board knee-high, the delicately shaded wallpaper an Arthur Rackhamesque dream of silver beech trunks with sinister faces traced in their boles.

It must have been a handsome home before the war. Now the pantry is bare and the children that the silver-haired brush-salesman Peter (Donald Maxwell) and his Dolly Messiter-ish wife Gertrud (Anne Mason) clearly waited a long time for – and maybe couldn't bear to send away as evacuees – have become a source of guilt and frustration. Who wouldn't cry over spilt milk when that is all there is for supper? Who wouldn't bury their nose in a bag of real coffee after months of chicory or acorns? And who, in the 1940s, wouldn't send their children out to gather berries unaccompanied?

Diligent and slightly priggish, besotted with her older brother, all knock-knees and jazz-hands in "Brüderchen komm tanz mit mir", Joana Seara's pig-tailed Gretel is a touchingly accurate eight-year-old girl, Catherine Hopper's tousle-haired, tough-guy Hänsel as easily distracted, unselfconcious and full of bravado as any 10-year-old boy. Sweet of voice, with beautifully direct diction and a radiant blend in the Evening Prayer, both singers convey a heartbreaking predisposition to happiness. Lulled to sleep by a Sandman in a sapper's uniform (Katherine Allen), serenaded in their dreams by the lollipop-bearing angels of the New London Children's Choir, and woken by a splash of soapy water from the Queen Alexandra nurse that is the Dew Fairy (Pippa Goss), their glee at the Battenburg pink-and-yellow gingerbread house resonates as strongly as their terror at what ensues.

For all the sophistication and perceptiveness of Acts I and II, Act III is pure storybook. With Mason doubling as the Witch, Barlow could have turned this into something rich with Freudian complexities. Instead, she is a lime green Edna Everage. If the children detect a resemblance to Gertrud, this is not made clear. Despite the pairs of empty shoes that tumble from her pram, hers is the least Auschwitzian oven I have seen in a production of Hänsel und Gretel and the opera has the most unequivocally happy ending. Under Peter Selwyn, the City of London Sinfonia deliver a cosy reading of the score, with some lovely details from the cellos, though the brass sounds more Elgarian than Wagnerian. Provided you can stand a stab of guilt if you've snapped at your children over breakfast, and provided they haven't been traumatised by the gas masks in Doctor Who, this is a very family-friendly show.

Unlike Eliogabalo. All Muscle Marys and biker clones, massage tables and tanning booths, sequinned G-strings and strap-ons, PVC and pole-dancing, David Fielding's X-rated production for Grange Park Opera appears to have been modelled on Vauxhall's modern-day pleasure gardens.

It's as good an analogue as any for the court of the cross-dressing, sexually omnivorous Eliogabalo (Renata Pokupic). But the nastiness of Cavalli's 1668 opera, which includes several brutal murders, is revealed too late to shock an audience high on high camp, champagne picnics, six-breasted statues and animatronic owls.

In the pit, Christian Curnyn seems anxious not to bore, zooming through the sensuous passacaglias, only slowing down when Claire Booth's Eritea spits, snarls and swoons her revenge arias.

Julia Riley makes a mean Alessandro, while Pokupic's lithe star turn is energetically supported by Tom Walker as a Pauline Calf-alike nurse Lenia and Ashley Catling as the tittering Zotico.

Back at Holland Park, Donizetti's Roberto Devereux is this year's Italian rarity. From the overture's ornate extrapolation of our sturdy National Anthem to the succession of pseudo-Baroque fugues, this is not a work for those to whom historical authenticity matters, though the score – performed with woodwind and brass to the right of conductor Richard Burgess Ellis, and the strings to the left – is exquisite. Designed by Peter McKintosh, Lindsay Posner's production moves at a stately pace. Eye contact is minimal and Yvonne Howard's gentle Duchess of Nottingham is the only principal to act when not singing. Excepting a bloodcurdling roar of "Va!", Majella Cullagh wisely saves her brittle, highly cultivated voice for Elisabetta's "Quel sangue versato", while Leonardo Capalbo's self-regarding Essex drifts about like a gust of expensive cologne.

"Hänsel und Gretel"/ "Roberto Devereux" (0845 230 9769) to 19/20 Jun. 'Eliogabalo' (01962 737366) to 5 Jul