No greeting. No welcome. John Stanier earnestly walks to stage centre and kneels on a red circular mat. Sleigh bells clutched in fist, his eyes cast south, he looks as if he's preparing for a ceremony or rite. As Shaman Stanier pounds the bells on his thigh, Priests Williams and Konopka stand either side of his umbrella-like ride cymbal and spread waves of noisy incense. This is ritual cleansing. Soon they will recite the 100th secret name of a band member now departed and then we can all move on. Please. Can we move on? Battles lost a member. He left almost a year ago. If he were a dead pet, we'd have a new tortoise by now.

However, a pet death, especially when it's elephantine and clearly still in the room is an unwanted intrusion, so we look to an acolyte named Young Montana? (intentional q-mark, it's part of his name) to provide some beat-based bereavement counselling. A floppy haired twelve-year-old hunched over a mixing desk and laptop, making an unwieldy, pointless racket. Between hiking his jeans up over his 21-inch waist and tossing his hair out of his eyes, Young Montana? desperately twists his mixer knobs with the determination of an angry boy trying to get the lid off his Ritalin. His directionless set fails to inspire more than three or four dogged dancers, who were already rhythmically shuffling about to the random pre-show music piped in while the venue was filling. Montana's retinue of samples are incongruous and unearned. Drum & bass meets Beach Boys and quickly agree to never again speak of their brief, shameful congress.

Several glances around the room during his twelve hour set show faces locked in boredom, or illuminated by phones. Sorry Young Montana? but as George Carlin said, "Not good Bruno. And not for sharing."

Losing a spoke of your cartwheel mid-journey will undoubtedly take you off the trail for a while. But only the unadventurous would abandon the cart in a shady ditch and return home, rather than fix the wagon's wheel and keep heading West.

Battles thankfully ventured onwards, with new horizons fixed in sight. To procure new spokes, Battles headed in every direction but West; guest vocalists on their latest release, Gloss Drop, have been gathered from Japan, Chile, and even our own smelly little island.

'Africastle' begins their set, as it begins the album. Throbbing and swelling upwards, promising. Ian Williams stabbing at his twin keyboards as Konopka, stage right, waits. Stanier continues his kneeling, nodding and bell bashing. At the perfect, beautiful moment he pounces upon his drumkit and pounds and pounds and pounds and pounds until all thoughts of grief, loss and some bloke called Tiger Brixton are driven from our minds with three wild, angry horses behind them. Williams skips and soft-shoes, a battered Gibson held at chest height firing off bursts over our heads. Corralling and cajoling a functionally dysfunctional family of two keyboards, two laptops, two guitars and a mixing desk. Now silence. Now a breath.

The music box chords of 'Ice Cream' are greeted with gleeful recognition and Matias Aguayo joins us astride two giant screens. The man himself may still be in Glastonbury shouting "Mis pies están atrapados en el barro!"

Song bleeds into song and we are led giggling through their toyshop. With the jarring surprise of a trick-or-treater looking through the letterbox in April, Gary Numan's head peers at us from the screens. He sings 'My Machines' sternly, like a gothic Dot Cotton asking us where our leather jackets are, and why our eyeliner isn't up to muster.

The three men jerk and sweat until the set jangles and careens to a glorious close. Dave Konopka offers the crowd an entirely suitable clasp-handed bow, the obligatory encore ensues and all is still.

Battles have mutated and evolved and become larger as three than they were as four. Through the inevitable initial damage that Braxton's flight may have caused, they have trauma-bonded, to use psychotherapy parlance. But any remaining doubts about their cohesion or creativity should now be buried.

A wag on Facebook recently suggested that Battles should "Change your name; you're not the same band now." I wonder if he would suggest a similar rebranding to any of the current members of Napalm Death, none of whom were there at the bands inception. Faith No More suffered no creative dearth at the loss of Jim Martin. In fact, their sound blossomed on the two albums that followed Angel Dust. Mayhem's black raging fire was never dampened, despite the quite theatrical loss of several members to depression, suicide and intra-band homicide. It fuelled them.

Metallica kidnapped Kirk Hammett from Exodus to replace the bona fide guitar genius of Dave Mustaine; their record sales were rudely healthy from that day onwards.

The point is that, were Battles a metal band, this debate would have never started yammering pointlessly around the internet. Bands like Battles are custodians and lifeguards of a vast musical gene pool, the DNA of which is complex, exciting and infinitely transmittable. It will always persist, proliferate and survive as long as musicians are open to fresh concepts and the odd bit of cross-species reproduction. Growth is vigorous, offspring are plentiful and hunting wounds are quickly cauterized. To reduce Battles to a list of members is to misunderstand them, and their class of composition, in quite massive terms. The Facebook wag was half right. They're not the same band now.