La Traviata, Holland Park Theatre, London<br/>The Seasons, Royal Albert Hall, London

Moving the action of 'La Traviata' to Paris in the Twenties helps make this new production ideal for first time opera goers

The weather was kind for the opening night of Holland Park's La Traviata, which hasn't often been the case this year. The venue itself – spruced up, with a new canopy, better bar facilities, and more comfortable seating – has become the place to encounter opera for the first time, and tickets are clearly going fast.

Not only is it an unthreatening environment for novices, with no dress code and informality the order of the day, but Holland Park is ambitious, too. This year, the company once again plays six new productions in a period of just over two months. That's quite an output. English National Opera, during its entire 10-month 2006-7 season, performed only 12 shows, and two of those – Gaddafi and Kismet – were outright disasters. Holland Park hasn't had a comparable failure.

Some of this quality is on display in La Traviata; first, in the striking designs, by Giuseppe and Emma Belli, which push the period forward from Verdi's own time to the Jazz Age. The Bellis' clean-edged sets provide the party scenes with a chic ambience for their smartly dressed Parisian hedonists to revel in, though they work less well for Violetta and Alfredo's rural retreat in Act 2 or for Violetta's intimate death scene in Act 3.

All three principals address their roles with vocal confidence and dramatic assurance, though only one of them consistently hits the spot. That's Robert Poulton as Germont père, who brings exactly the right blend of vocal gravitas and bourgeois outrage to the part, and yet manages to make a character who usually registers as blindly moralistic seem almost humane.

Seá* Ruane clearly finds Alfredo a more congenial role than some of his heavier assignments at Holland Park. The odd metallic moment apart, his tone flows freely, though he has difficulty moving it around the faster notes quickly enough. But physically he moves well, creating a credible realisation of a callow young man out of his provincial depth in sophisticated Paris.

Kate Ladner is not quite the star required for the challenging title role. She lacks sufficient magnetism to win the audience to her emotional cause and hold them to her through thick and thin. She also lacks a secure E flat to go for at the end of Act 1, in which case it's probably best not to attempt it. (Some of the most distinguished exponents of the role prefer to play safe at this point.) But her characterisation is along the right lines and, taken as a whole, she's touching.

So is Elaine Kidd's production, though it has its entertaining moments, with a bevy of camp waiters flouncing the furniture in and out as required. As an entity, this Traviata makes a solid impact.

John Gibbons's conducting does something more. He shows a precise understanding of Verdian style and motivates the score from start to finish, while in the pit the City of London Sinfonia makes a more than decent showing. The whole amounts to a very acceptable evening out, and with a top price of £46 you can't say fairer than that.

Except possibly down the road at the Proms, where a top-price ticket for a performance of Haydn's The Seasons on Monday would have cost you just £25, or £5 to stand. And, for that, you would have heard over two hours of great music memorably performed by soprano Sally Matthews, tenor James Gilchrist and bass-baritone Jonathan Lemalu, with the choral and orchestral forces of the Handel and Haydn Society of Boston, all under the benign baton of Sir Roger Norrington.

The BBC wasn't quite so lucky with the weather: a cold, wet night must have affected the queue of Promenaders. The result was a less than full house for what is arguably the most enjoyable oratorio ever written.

With a theme like the seasons, there's an inevitable concentration in the libretto – based on James Thomson's early Georgian poem of the same name – on matters meteorological. "The midday sun now blazes at full strength, beating down through the unclouded sky in mighty waves of heat," sang Gilchrist in Part 2: Summer, without a visible hint of irony. (I quote the text in Avril Bardoni's translation, printed in the programme book.) Not this particular summer, though Haydn's original Viennese audience in 1801 might have been used to a more traditional climate than a UK audience in 2007.

Gilchrist and his colleagues sang marvellously. His flexible tenor moved elegantly around Haydn's notes and his delivery of the text was strikingly vivid. Lemalu's tone blasted out with fervour when announcing winter's defeat and the coming of spring, but he sang with airy lightness as he described the ploughman plodding his weary way homeward. Matthews was in gorgeous voice, her gleaming soprano rising with ease to the highest heights.

Much of the charm of the piece comes in Haydn's picturesque nature painting: light touchings-in, often orchestral, of just about every reference to living things and natural phenomena that the text throws up, from frogs to owls to sunrise. The Bostonians went for every tiny detail in the vast canvas, highlighting them all with wit and affection.

So did Norrington, who has developed a neat little act halfway between a showman and a barrow-boy for these occasions, turning to the audience with an applause-inviting gesture the moment one of the more brilliant sections – the storm, the hunt, the drinking song, and so on – has reached its final chord.

And why not? The Seasons is a delight, and like any great salesman, Norrington knows when he has a hot product on his hands.

'La Traviata', to 11 August (0845 230 9769); Proms, to 8 Sept (020-7589 8212). Further reading 'Haydn: His Life and Work' by H C Robbins Landon and David Wyn Jones (Thames & Hudson)