Nearly 50 years have passed since Britten’s War Requiem premiered at the consecration of the reconstructed Coventry Cathedral in May 1962. The intervening years have seen British military campaigns in the Falklands, Iraq, Afghanistan and Libya, and while the process and practice of war has changed beyond recognition, the horror that the pacifist Britten perceived so acutely remains the same.

While revered and respected, Beethoven’s Missa Solemnis has never inspired audiences with the same affection as Bach’s B minor Mass, Haydn’s Nelson Mass, or even Mozart’s Coronation or C minor settings. Perhaps it’s the austerity, the monumentality of the work Beethoven knew to be his greatest that rejects the easy assimilation into secular concert life, perhaps it’s more simply the lack of big tunes to wash down all that liturgy. Furtwängler famously drew back from the work’s sacred challenges as he grew older, but Sir Colin Davis is evidently determined to keep tackling a work whose performance he has likened to “failing to reach the top of Mount Everest”.

There are many ways to get to the truth. One of the best ways is to ignore the truth. That seems to be the mantra of Ken Russell's colourfully mendacious portrait of the composer Pyotr Ilyich Tchaikovsky, The Music Lovers, receiving its long-awaited DVD release.

This week we’ve a brilliant, budget-priced box of Beethoven symphonies played on authentic instruments. It’ll remind you of how much fun there is to be had with this most iconic of composers. A historical recording of a famous cellist reappears, but the best reason to listen to the disc is to hear a famous Czech conductor achieving miracles. And there’s an entertaining, educative DVD featuring a conductor who’s in his element when addressing an audience.

It was Groundhog Day. Murray Perahia, due to play the Schumann Piano Concerto last night under Bernard Haitink, was indisposed and at the last minute Maria João Pires rushed in with Mozart 27. Just the same happened in 2006, strangely enough, with exactly the same three artists and orchestra. As you ponder that for a coincidence, what this shows is the powerful bonds that exist between musicians, between Haitink and these two pianists, whose virtues have much in common: impeccable lucidity and light-filled emotion.

In a week in which the nation has debated the relevance of classical music, it was left to the LSO’s Eclectica concert series to have the final word. Incorporating world and electronic music alongside traditional chamber works and contemporary programmes, Eclectica’s concerts offer dressed-down, laid-back forays down the roads less travelled of the classical repertoire. With one of the 20th century’s musical greats as a grandfather and a growing reputation for his work as a producer, DJ and composer, incorporating classical music into a club idiom and setting, who better than Gabriel Prokofiev to weigh in on the debate?

This week we review Bellérophon, a rare Baroque opera from Lully which was exhumed by Christophe Rousset and performed for the first time last year, Debussy recorded live from the Barbican, and we answer the key question: how much is too much Percy Grainger? Would, for example, 19 discs be considered sufficient?

It's just been crowned the BBC Music Magazine Awards' CD of the Year. But is Valery Gergiev's second complete recording of the 20th century's greatest ballet score, captured live at the Barbican for the LSO's own label, right at the top? In my Building a Library survey for BBC Radio 3, condensed in print for the BBCMM, I suggested it might be the best in state-of-the-art sound - but not the finest overall version of Prokofiev's Romeo and Juliet. That palm went to Rozhdestvensky's much more impeccably paced old Melodiya version, in mono and dating from 1959.

Heavy-goods vehicles stacked with lamentations have been thundering through the Barbican Hall. Saturday's lugubrious Rachmaninov found a mid-20th-century counterpart last night in the tough elegies of Shostakovich's First Violin Concerto - apt for a dedication to those affected by the Japanese earthquake. And the tottering juggernaut of not-quite-great-but-living Russian composer Rodion Shchedrin still clogs the LSO's current season, fortunately in this case only to head a procession ending in the carnival float of what should have been Tchaikovsky's springiest symphony.

Sir Colin Davis's year has not been a happy one. There've been heart problems, cancellations and, during a performance of The Magic Flute at Covent Garden last month, a major fall. Last night at the Barbican Hall he faced a strenuous Beethoven programme, the Third Piano Concerto with Jonathan Biss and the Seventh Symphony, and a new work by Romanian Vlad Maistorovici. Would the 83-year old conductor have enough energy to inject proceedings with the required welly?

There was as much welly as you could wish for. Understandably, he had assigned the mastery of Maistorovici's Halo to an undertsudy, Clemens Schuldt. It's not a particularly complicated piece but still no doubt benefited from the undivided attention of this young man. Its ebb and flow, most of which takes place in brass, woodwind and percussion, undergirded by a regular arpeggiated beat on strings that both harries and rocks, was reminiscent of Sibelius. A brief languid passage gives way to a faster, more colourful one that brings in snatches of Bartók and Stravinsky but that ultimately fails to shake off the rather suffocating beat, which rang on in the head after the work ended.

This was broken by the two lightning flash runs that announced the arrival of Beethoven's Third Piano Concerto and pianist Jonathan Biss at the keyboard in terrifically dramatic mode. It cut through a sluggish tempo that Sir Colin seems to have opted for for the opening orchestral statements. Biss took control of the reins and appeared to re-invigorate Davis who tarried with a much more suitably moody response. Biss's was the account of a true troubled traveller, full of changes of character - now the shouter, now the singer, now the imp - subsumed into one coherent and compelling voice.

The Largo saw some excellent pedalling that bled colours but never swamped them and the lolling head of the piano was perfectly put to sleep and then roused to action. Just as well. There are strange apparitions to be encountered in the mostly jaunty Allegro con brio and both Davis and Biss relished the arrival of every single one.

But how would Davis cope with that ultimate young man's work, the dashing romp that is the Seventh? With all the consummate ease and power of one of the world's great Beethoven interpreters. There was none of the colouristic reinvention of the Dudamel performance with the LA Philharmonic last month. But there was also no cutting of corners. Most importantly, and happily, there were very few signs of the tiredness that Davis seems to have been suffering from recently. This was a spirited performance, full of spring, brio and no small amount of fury. Speeds were fast but consistent. Woodwind were always able to graze quite happily in their fragrant clearings.

His attention was to the broad, natural sweep of the symphony rather than the many fine inner voices, the petticoats that can be admired and fiddled with till the cows come home. In this way, the melodic thread, which sometimes gets lost in lesser hands, was carried through every part, from the Verdi-like whirlwind of a dance in the Scherzo to the sinking double basses and singing horns of the finale. A masterclass in the art of conducting Beethoven had unfolded before us.