A good music documentary can get you excited about an artist or scene you’ve never heard of, but this one, on Glasgow indie label Chemikal Underground, assumes you’re already a convert, and probably a middle-aged bloke. Even if you are, you might feel slightly deflated by this subdued nostalgia trip, which returns the label’s key figures (chiefly, members of the Delgados and Mogwai, plus Alex Kapranos, latterly of Franz Ferdinand) to the French town of Mauron, where they played an apparently seminal festival in 1997. “Apparently” because there’s virtually no record of the original event. Instead, we get six musicians reminiscing about the 90s glory days before playing a low-key gig in a cafe. The musicians are talented, thoughtful and charming, and their story says plenty about the decline of the music industry. But it feels like we’re getting the comedown without having had the high. They’d have been better off staying in Glasgow.