"What's your angle, then?" he asks. Since last meeting with the press, Supergrass's youngest member has lost a parent and become a father. He knows I'm not here to ask what his favourite colour is.
Coombes's elder brother Rob is also present. A slightly hippie-ish man who joined Supergrass on keyboards in 2002, Rob has a degree in astrophysics. While Gaz and Quinn are garrulous, Rob only pipes-up twice. Conspicuous by his absence is the drummer, Danny Goffey.
We have met to discuss their fifth studio album, Road to Rouen. Its playful title sits nicely alongside those of their previous records, such as I Should Coco and In It for the Money, but it also flags up a musical direction that may be the band's undoing as a singles act. Road to Rouen is an idiosyncratic record that Quinn calls "a bit of a grower". But it's not for nothing, you suspect, that Coombes sings of "commercial suicide" on the first track, "Tales of Endurance Parts 4, 5 & 6".
The album was recorded in a barn 30 miles outside Rouen. In a process not dissimilar to one of those A Place in France-type reality TV shows, the band kitted out a run-down cottage purchased by Gaz and Rob, then bought, begged or borrowed gear for their studio. "You get fed up with the results you get in professional studios," Coombes explains. "Everything sounds so crisp and perfect. We wanted to push things sonically, produce our own record and blag it a bit. We used this old well outside the barn as an echo chamber, and stumbled across all these great sounds."
Working in 10-day stints, the band did their own cooking and didn't fret when the sound of boiling pasta leaked into acoustic guitar microphones in the kitchen. Down time was spent watching movies and trying to catch the local hens' eggs before they hit the ground.
"We didn't ride around on bikes with strings of onions around our necks or anything," says Quinn, "but we got a feel for the place."
Idyllic though this existence might sound, the backdrop to Road to Rouen's gestation was actually rather testing. Goffey took a tabloid grilling over allegations of wife-swapping with Jude Law and Sadie Frost and the Daily Mirror's report that he and Pearl Lowe's 15-year-old daughter Daisy was actually fathered by Gavin Rossdale, the singer with the rock band Bush.
"Because we all grew up together we're still looking out for each other," says Quinn. "Danny's always been quite wayward, but his heart's in the right place. Supergrass wouldn't be the same without him, that's for sure. He was a bit uncertain about things towards the end of the album, but we've moved outside our musical comfort zone."
By the band's own admission, "Pumping on Your Stereo" or "Sun Hits the Sky"-type songs - obvious hit singles - "didn't turn up" this time.
"We've reached plateaux in the past where we've sold lots of records," Coombes says, "but we're often reactionary to our successes. It's not a negative thing - it's more about how we survive in music. This time we tried to capture the spirit of all the stuff we've recorded at home. We didn't want to chicken-out of recording bizarre, crazy stuff."
"Tales of Endurance" packs Led Zeppelin-esque acoustic guitar, mariachi brass and a Franz Ferdinand-like freak-out. The single, "St Petersburg", is a lazy, brushes-on-snare conceit with upright piano and a zither solo. Lyrically, one of the most affecting tracks is "Roxy", wherein Coombes sings: "Hello my honey/ My beautiful friend/ It's hard to imagine/ It's come to an end." The song was written in tribute to Gaz and Rob's mother Eileen, who died of cancer in October 2003, aged 59.
"Yeah, there are moments of real sadness on this album," says Coombes, "but hopefully not too many. Mum dying was the biggest tragedy in my life and my brother's, so it was always going to creep into the songs."
Supergrass formed in Wheatley in 1994. Prior to that, the younger Coombes was in an indie act called The Jennifers with Goffey. "We only released one single before Nude Records dropped us," says the singer, "but it gave us knowledge about the business, certainly." Gaz, Rob and Quinn bonded while working at the local Harvester restaurant. Gaz suggested they jam with Goffey, and everything clicked.
The group's 1995 debut I Should Coco stands as one of Britpop's finest hours. Including "Caught By the Fuzz", Coombes' account of being busted for possession of marijuana aged 16, it is an exuberant record. The "Alright" video showed the band as cartoonish figures freewheeling on Chopper bicycles.
"Even then, we knew exactly what kind of band we wanted to be," says Coombes. "We wanted to be like those strong, independent Sixties bands who dictated their career paths."
"We admired bands like The Cure, too," adds Quinn, "bands who had their own image and musical identity down before anybody had written a review."
The follow-up, 1997's In It For The Money, was billed as a "Supergrass grow up" record, although the news soon broke that Steven Spielberg, no less, loved the video for "Alright" and wanted to film a TV series based around the band's cheeky chappie antics; an update on The Monkees.
Coombes: "We were offered a trip to Universal Studios to meet him that summer; bring our families; whatever. We went, of course. He was an interesting, friendly guy."
Quinn: "At the end of the meeting we said we'd think about the TV series, but ultimately it didn't suit us. We were worried that if we got set-up for life cash-wise, we'd forget about the music, and we were already making an album that represented us better than anything Steven Spielberg could have done."
Coombes: "Our suspicion was that his kids had seen the video for 'Alright' and said, 'Daddy, can you buy us that band?'"
Still, doesn't Coombes regret turning-down that underwear deal with Calvin Klein?
"Nah," he says. "I can still put my daughter through school, thanks. We've got some cash. We've got some houses. The boys did good. The last thing I want is to look back on my life and see that I advertised boxer shorts. Those early photo-shoots we did wrapped in Clingfilm were bad enough."
'Road to Rouen' is out on Parlophone on 15 AugustReuse content