Lenny Henry: “Over the past few months I have been enthralled and captivated by the story of a man from Croydon in south London who died more than 100 years ago and who wrote one of the biggest musical hits of the [early] 20th century. He was a total genius – a bit like Prince, but for late 19th-century London rather than 1980s California – and his name was Samuel Coleridge-Taylor.”