It takes a certain kind of man to saw off his own frost-bitten fingers at the suggestion of his wife, who felt that the pain was making him tetchy. But, as this fascinating film details, the “world’s greatest living explorer”, Sir Ranulph Fiennes, is no ordinary chap. And his relationship with his first wife, his tireless supporter and fundraiser Ginny, was equally singular. You suspect that she might have suggested the auto-amputation in part because it was exactly the kind of colourful anecdote that would play well with the sponsors who lived vicariously through Fiennes’s polar adventures. The approach of director Matthew Dyas, who gives the archive material the appearance of found footage, adds to the mythic romance of Fiennes’s life story.