The lesson to be learned from Michal Sulima’s documentary is that if you’re planning to transport a piano to a village school in the Himalayas by yak, it’s advisable to first meet a yak – or at least Google one beforehand. Not having done due diligence, when 65-year-old piano tuner Desmond O’Keeffe turns up in India he discovers that yaks are a bit too titchy to carry his 100-year-old Broadwood & Sons up and down mountains.

There is a lot of charm to this film about O’Keeffe’s quixotic (bonkers would be another way of putting it) expedition to deliver a piano to a village in Zanskar, northern India – making it the highest in the world. He’s an endearing eccentric who says he can’t face retirement on a deckchair “eating lemon drizzle cake”. He got the idea for the trip from a customer at his Camden Market workshop, who’d planned to take a piano with her to teach at the school, but got pregnant and couldn’t travel. Somehow, the idea glued itself to O’Keeffe’s imagination. The village is a two-day trek from the road – and in the end the piano is carried by porters.

There are echoes here of the grandiose mission in Werner Herzog’s movie Fitzcarraldo to haul a steamship over a mountain. But O’Keeffe is no Klaus Kinski; he is horrified when the piano threatens to pull seven or eight porters down the side of a mountain like an avalanche. “I wouldn’t put lives at risk for a piano,” he repeats afterwards, over and over again.

Some might feel that his mission smacks of iffy cultural high-handedness: who is he to bestow this grand gift of music on people who have their own vibrant musical culture, thank you very much? But with O’Keeffe’s openness and warmth, it genuinely doesn’t come over like that. Though I wondered if spending a bit more time with the sherpas would have added another layer of understanding to the film.

• Piano to Zanskar is released on 19 November in cinemas.