We're warned: Walk into Brixham Fish Market in Devon while wearing green wellies, and the likelihood is you'll be met with farm noises.

White and yellow wellies are the way forward if you want to mingle authentically in the chilly, early morning world of the fish market, a-bustle with fishermen who drink together on the weekend, but compete daily in the market.

However, we are not professionals, so instead, our guide James Mooney, from seafood wholesaler and fish supplier Kingfisher Brixham, has us decked out in plastic slip-on shoe covers, hair nets (very fetching) and white coats, as though we're about to enter a medical lab.

Pushing our way into the warehouse, with its makeshift vibe and sales screens gently scrolling on the walls, it may not be all that clinical or smell of formaldehyde (the fishiness isn't even that strong), but amongst the welly banter, there's a precision to the bidding - the result of much analytical studying of the fish, which are laid out on the floor in uniform white tubs that slosh with ice.

The rule is you buy by the box, explains Mooney, who wryly notes that the fish are caught by fisherman often handling boats named after their ex-girlfriends...

You can't just walk in here off the street and start haggling over scallops, though. Tours are available, but you have to pay a bond to actually buy the fish, and anyway, a novice would struggle to navigate the tactics involved - and the relationships required - to bid in person, "which has been the way for hundreds of years", Mooney notes.

"A new clock bidding system starts in January, though," he adds. "The fishermen should make more money, but it's a shame."

We're here with chef and seafood champion, Simon Hulstone, of Michelin-starred restaurant The Elephant, which is found in his nearby hometown, Torquay.

We stalk between crates of mottled Dover sole; inky lobsters with their taped-up claws still trying to clack; huge slabs of turbot flop belly up; and box upon box of red mullet - a bycatch - which shimmer crimson and fuchsia. "Chefs want the pink scales," says Hulstone, "but they get battered when they're caught."

Most eerily, there are tubs containing severed, alien-like monkfish tails, which historically have been used as scampi (the deep-fried stuff you get at the pub): "The fishermen bring them in headless because the head is as big as the body," explains Mooney - and there's not much to be made from the heads.

Mooney and Hulstone talk fish trends (the fishermen are keen seafood trend followers); how chef Tom Kerridge's now famous deep-fried brill and chips at Kerridge's Bar & Grill - for a whopping £32.50 - is worth every penny ("It's brill!" yelps Hulstone), and why British restaurant-goers aren't interested in eating 'black gold', aka cuttlefish, which, like a lot of crab, is bought up by other countries.

You feel as though you've breached a whole other world just being inside Brixham Market, then on your way out, huge seagulls clatter around diving for scraps, and your taxi driver informs you that yes, you really do stink of fish, even if you can't smell it yourself.

Back at The Elephant, which Roux scholarship winner Hulstone runs with his wife, Katy, who manages the front of house, he demos three of his dishes, filleting halibut, hake and cod in swift succession.

Hulstone is a big supporter of Brixham but is also a major fan of - and ambassador for - sustainable Seafood from Norway, including skrei cod and Glitne halibut, from Norway's fjords. "It's all about heroing the product," he says with reverence.

He has fewer than 10 people in his kitchen and considers himself the "conductor at the front", while interestingly, his apprentice James, doesn't even like eating fish.

"I don't like the way it's made," James admits sheepishly, when quizzed over the carcass of a glistening halibut. Hulstone is working on him though; putting peoples' indifference and dislike of fish down to the fact "batter has blinded us". It's hard to dispute that many of us would be utterly stumped if faced with a whole fish on the bone. "It's an animal, it's got to move, it's got to live, it's got to bleed - people forget that," explains Hulstone.

That said, he's very strict on getting rid of any "uglies" - whether you're cooking fish at home, or being served it in a restaurant.

"Always check the inside is really nice and red, no smell," says Hulstone, reeling off what to look for when selecting a fish, either from your supermarket or fishmonger. "The less handling the better, or it degrades." And that icky fish slime you get? "That means it's fresh."

But don't be put off buying frozen fish. If the label says 'frozen at sea' he explains, it means the fish has been filleted and frozen on the boat, within two to four hours of being caught - so it should end up being considerably fresher than stuff that's just been chilled and transported back to the mainland.

"People think it's being a cowboy, freezing your fish," he says. "It's not, it tenderises it - it's exactly the same, even though it can seem like a cheat."

And if you're anxious about filleting your own fish, there's no shame in asking your fishmonger to do it for you - even Hulstone still gets nervous filleting, especially when he's faced with deftly slicing a three to four kilo sea creature into fourteen identically sized and shaped portions for dinner service.

Slapping a fillet of cod in a hot pan with butter sounds very much a doddle in comparison.

Simon Hulstone has teamed up with Seafood From Norway (seafoodfromnorway.co.uk) to demystify cooking sustainable Norwegian cod, haddock and halibut at home.