Why does music suddenly disappear? It is all the more heartening when a work as excellent and enjoyable as Louise Farrenc’s Symphony No 3 takes wing once more, but you do have to wonder how in the world such a terrific orchestral piece was permitted to sink and vanish in its day under a morass of dubious opera.

At this time of year the musical world – and particularly the choral world – is full of festive concerts, and the challenge can be to find programmes venturing off the well-worn path of traditional favourites.

It’s 10 years this month since Kate McGarrigle gave her last concert, the annual Christmas concert that meant so much to her, at the Royal Albert Hall. Next month, 18 January, marks the first decade since her passing at the tragically early age of 63.

Happily, Joe Barton’s tinglingly original thriller (BBC Two) finished as smartly as it began, not by any humdrum tying-up of loose ends but by giving free rein to the story’s ambiguities and impossible choices. If indeed they really were choices.

Given the number of audience members playing air-piano along with parts of Pictures at an Exhibition, Behzod Abduraimov should perhaps be described as a pianist’s pianist. He is nevertheless a great deal more than that. Ten years ago this young musician from Uzbekistan, via Kansas City, emerged victorious from the last-ever London International Piano Competition; he was 18 then and if his artistic growth thus far is anything to go by, we are dealing here with a rare and enchanting musician.

It’s always good to be among friends and it’s safe to say that everyone gathered at Islington Assembly Hall on Saturday for the third and final North London gig of Billy Bragg’s One Step Forward, Two Steps Back Tour was left of centre. The tour began in July on the south coast, planned long before Borrissey, as Bragg calls the PM, conned the country in going to the polls but events have certainly given it a new urgency.

The four young men who comprise Darlingside met at Williams College, in the Berkshires which, each October, declares a “Mountain Day” when students hike up Stony Ledge and celebrate with donuts, cider and a cappella singing.

There aren’t many musicians who could appear as composer, singer and violist on a single programme but that was Caroline Shaw’s lot last night.

It’s been 15 years since Cameron Mackintosh’s stage musical version of P. L. Travers’ Mary Poppins made its West End debut.

Ian McKellen, his Mr Holmes director Bill Condon and Helen Mirren play clever, nasty games with conman clichés and presumptions about the elderly in this sometimes absurdly twisty thriller.