This tour offers two Mercury Prize nominees: both groups have occupied the slot on the shortlist reserved for acts that record in sheds, whose victory would be a cause for delight but is improbable in the extreme.

Success has not yet spoiled Sweet Billy Pilgrim, who still amble on stage like three physics students and a Young Farmer, and who still visibly tinker with tunings and equipment. But their glitchy rock has toughened up, even if its melodies still swim just below a surface film of electronic bric-a-brac.

“Future Perfect Tense”, which would be their hit single if they had anything so vulgar, now hits hard, with rolling waves of thrashing guitar. “God In The Details” starts as a berserk waltz but has a sumptuous rising coda. “Joy Maker Machinery”, introduced by Tim Elsenburg as a song about sex, unfolded with a languorous rhythm at odds with biology. “We are engineers/we are architects”, he sang at the climax.

Portico Quartet’s Mercury nomination bought them a needle-precise production job from John Leckie for their second album, Isla. For a couple of minutes they felt formless but the music then resolved into the fragile hardness of “Paper Scissors Stone”, and they flew.

Their trademark sound is the hang, a steel pan that mimics the sound of a gamelan. Nick Mulvey had his mounted on tripods, looking like a model village War Of The Worlds . The hangs create colour, rhythm and pattern; they also anchor the music, as they coalesce into a blur if played loudly. Jack Wyllie’s soprano and tenor saxophone (and occasional tiny xylophone) were the main melodic instruments. On record his playing lands somewhere between Steve Reich and Moondog; here, he was wilder, more improvisatory. “Knee Deep In The North Sea” washed back and forth on breakers of drum and hang. “Line”, which would be the quartet’s hit single if they had anything so unlikely, was gloriously extended, Mulvey coaxing a couple of minutes’ shimmer from the hangs before the band took up the rhythm and Wyllie soared over the top.

Tour continues throughout November