The balmy summer Saturday night in Cambridge had a slightly wild west ambience when we arrived in town for dinner at Mercado Central. E-scooters for hire have arrived in the city centre, which is terrific fun for everyone: riders, pedestrians and road-users alike. Who doesn’t love palpable chaos and an incessant moving backdrop of near-death collisions? I know I do. Or at least, I learned to live with them.

However, I genuinely do love authentic, modern-facing Spanish restaurants, showcasing simple, ancient Basque and Galician techniques and exemplary local produce, which is why I was away from my sofa and 50 miles down the M11 in search of one of those Nieves Barragán Mochacho-style gooey-centred heavenly tortillas that defy home replication, or even some simple but meaningful pan con tomate or a bowl of judiciously balanced fideua. Because my prior impressions of Mercado Central seemed to say it was this type of place: set within a beautiful old Cambridge townhouse, its outer brickwork painted navy blue, with an elegant upstairs dining room and, on the lower floor, an open kitchen.

By God, I wish I’d insisted on being seated upstairs. Instead we sat downstairs, in what I read later on the website was a bar area; this despite having booked a table many, many moons ago. Our seats backed on to an echoey, empty fireplace where the fire extinguisher lived, near to the footfall of the front door, adjacent to the hectic open kitchen where serving staff buzzed about without direction or left to smoke cigarettes. In order to be heard by your dining companion, you needed to shout, and thus everyone in the room was shouting. The remedy for this seemed to me to be a large, stiff Mercado lemon verbena gin and tonic. Perhaps then, I figured, the din and disorder would start feeling like a hazy night in Palma de Mallorca, wandering around the old town’s backstreets, chancing upon that family-run, slapdash, no-frills grill that transpires to be the shining pinnacle of your holiday. I necked the gin and lip-read our server as she filled us in on all the delicious items on the brief menu that were no longer available as they’d sold out. “Queen scallops and gambas al ajillo … are off the menu,” she said, in the manner of Jim Bowen pointlessly showing me a speedboat.

We ordered a plate of cecina de Wagyu & Cebon, a cured meat from Leon, and the Arzua cheese and piquillo pepper croquetas. The croquetas were Wotsit-orange and perfectly edible, albeit one-note in flavour and not terrifically crispy. The cecina was fine, but it was sliced cold meat on a plate so they’d not had much input. A plate of white asparagus with lemon mayonnaise was both waterlogged and mushy and the crispy squid had been deep-fried until it was nigh-cremated.

By this point, we’d spent around £60, eaten little and were still waiting for something delicious, but I was in no mind to give them £85 for a Tomahawk steak. Instead, I tried the baby leeks (slightly stewed), parsley, chopped egg and anchovy (singular, it was literally one very good anchovy cut into pieces.) “Perhaps we can go off-menu and ask them for a plate of these anchovies. They actually taste of something,” shouted Charles. “No, we can’t,” I shouted back. “Only dickheads order off-menu.” Charles, being French, finds this attitude incredibly British.

Instead, I ordered tarta de limon, hoping for something delicate, dense and zinging with Valencian groves, set serenely within buttery shortcrust. I received a warm piece of lacklustre garden-centre-cafe lemon meringue pie. At this point, the chef plodded past to go for his cigarette, too. El Bulli this is not.

And here lies the problem with this new breed of fancy, pricey, British yet apparently “Spanish” restaurant, which says: “You’re not in a tacky tapas place now – don’t go expecting chunks of Lidl chorizo fried in port or mystery meatballs or Julio Iglesias’ Begin the Beguine on the stereo. Have you not been to London’s Barrafina or Sabor or that Quique Dacosta joint where they charge you nearly £100 for a small, charred prawn paella? We’re like that! We’re fancy people here! Bring your credit card. Let us educate you.”

Because when all that ambition falls flat, all you’re left with is a hefty bill, tinnitus and a craving for a humble plate of substandard patatas bravas. Mercado Central is a beautiful building with, on the ground floor, the makings of a pleasant place to drink vermouth or sangria. With more careful, generous cooking it could represent Spain beautifully, but right now it’s firmly in the red zone.

• Mercado Central, 24 Green Street, Cambridge, 01223 502392. Open Mon-Thurs 6-11pm; Fri noon-3pm, 5.30pm-11pm; Sat noon-11pm; Sun noon-5pm. From £35 a head, plus drinks and service

• Grace’s podcast Comfort Eating is out now. New episodes are released every Tuesday. Search Comfort Eating with Grace Dent online, or listen wherever you get your podcasts