Once the alternative music fan’s holiday camp-based festival of choice, All Tomorrow’s Parties has had a troubled recent history. The promoter’s business practices recently went from being the target of indie messageboarders’ ire to attracting the disapproving attention of Private Eye. The regularly liquidated and resurrected company has cancelled and relocated events at a moment’s notice, debts and refunds have gone unpaid, and only a few weeks ago Pontins was informing inquisitive emailers that the event, curated by the comedian Stewart Lee, would not be going ahead.

In the end it does go ahead, if not entirely smoothly. Saturday’s headliner John Cale pulls out the day before he’s due to perform, tweeting that the bookers “let us all down”. Having come all the way from Austin, Texas, 60s psych pioneer Roky Erickson agrees to play his set “for you guys”, despite having “not seen eye to eye with a certain organisation”. Lee shrugs off accountability by beginning his “hits” set with five minutes of jokes about the acts due to play the third stage being transferred to Manchester, accessible via shuttlebus, and advising customers to direct all chalet-based complaints to 80s post-hardcore heroes Mission of Burma.

Not everybody is unhappy. Of all people, austerity antiheroes Sleaford Mods announce that ATP “have really looked after us”. Like Lee, the laptop-punkers have acknowledged the ironic dilemma of gaining lucrative popularity off the back of an underdog persona. Still, while the experience may not be as rousing as seeing them perform in your local sticky-floored toilet venue, the Mods prove able to fill a large festival stage with just two scruffy members, a computer, a microphone and a lifetime’s worth of pent-up rage.

Saturday sees Lee’s beloved the Fall promoted to Cale’s empty slot. Looking like a besuited cross between a sozzled frog and exile-era Napoleon, Mark E Smith growls through a number of different microphones, the principal one making it sound like he’s singing through a dented kazoo. The set threatens to peter out at the halfway mark when Smith turns his guitarist’s amplifier volume to zero and instructs his group to leave the stage. But they’re soon back for a searing rendition of Theme from Sparta FC, followed by further barked new wave numbers and an encore which Smith sings from behind a curtain.

Given ATP’s woeful reputation, the festival is surprisingly busy. Its concert halls are packed with punters enthusiastically lapping up the supposedly niche music of Ex-Easter Island Head, who literally mallet their guitars to create crashing Sonic Youth-meets-Liars no-wave instrumentals, and even Skatgobs: three grown men who make half an hour of guttural gibberish noises without any musical accompaniment whatsoever. Rapturous responses are received by cult psych-rock groups such as Philadelphia’s mind-warping Bardo Pond, fronted by effortlessly cool singer and flautist Isobel Sollenberger, and Bristol’s the Heads, presumably named after the body part they best like to bang.

Clearly there’s still a market for connoisseur-curated seaside festivals showcasing alt-music legends and esoteric curiosities, even if ATP’s capacity to deliver may be diminishing for good.