At times it’s a story that almost beggars belief. Searching For Sugar Man, if you’ve not seen it already, is a documentary about Sixto Diaz Rodriguez, the 70-year-old singer-songwriter from Detroit who released two glorious, largely unheard albums some four decades ago, then promptly vanished without trace. Various grisly rumours about his unfortunate life – murder, suicide, jail time – began to circulate in the intervening years. Meanwhile his records had become huge in different corners of the world. Not least in South Africa, where his baroque-folk protest songs had become beacons of hope amongst anti-Apartheid campaigners.