Teenage Fanclub have some history with this bandstand. They filmed a DIY video in its vandalised shell over a decade ago and became high-profile supporters of the campaign to restore it. For guitarist Norman Blake, the association goes back even further. "It's really nice that they've rebuilt this place," he tells tonight's sold-out crowd. "I have fond memories of glue-sniffing down here in the 1980s."

Never mind saving the venue – some longstanding fans may have been considering a campaign to bring back Teenage Fanclub. Since their Shadows album in 2010, the gifted song-writing triumvirate of Blake, Raymond McGinley and bassist Gerard Love have been exploring other musical outlets (with the New Mendicants, Snowgoose and Lightships, respectively). With so many satellite concerns, is the beloved powerpop mothership still viable?

By the time they play their second song of the night, the joyous Ain't That Enough, it's clear Teenage Fanclub remain as simpatico as ever. Their sweetly crafted songs still resound with empathy, enhanced by harmonies exceptional enough to suggest telepathy. It's a sturdy performance, but for the first half of their 18-song set, the amphitheatre audience remains admiring but inert. The chiming, cosmopolitan I Need Direction, a song that on record features the sound of a revving moped, might not seem like an obvious riot-starter, but it becomes the tipping point for a significant proportion of the crowd to abandon their seats and funnel toward the stage.

This well-mannered invasion is quite a sight, and seems to come at the perfect time. "Thanks for doing that," says Blake, as the band go on to revisit some of their earlier, more heavily distorted jams. The Concept is still potent enough to spark a serious moshpit, and when they close with the cathartic grunge of Everything Flows, it generates a feedback loop between the band and their fans that feels genuinely triumphant.