36 Dean Street, London W1 (020 7432 4800). Meal for two, including wine and service, £110

I remember eating at the very first Hotel and Bistro du Vin in Winchester, in the mid-90s. It's not a night either my wife or I could forget. Blighted by infertility, we had started a course of IVF and gone away for the weekend because we would know the outcome that Saturday. The pregnancy test came back negative, and by the evening we were ready to eat and drink like nothing mattered, because it didn't much. It should have been a desperate, miserable meal, but it wasn't, and so much of that was down to the Hotel du Vin itself. The sommelier Gerard Basset and hotelier Robin Hutson had put together a seriously classy act – a smart, vaguely boho space full of guttering candles, painted wood panels and tasteful art. The staff were efficient and relaxed without being pious, and there was an eclectic menu of very 90s food – I recall a very good Thai crabcake with a sweet chilli jam – cooked by a thin, enthusiastic Yorkshireman in a bandana called James Martin. I wonder what became of him.

Because of that night, I have always been very fond of the hotel chain. Even when the founders sold out and it became part of the same group as the Malmaisons, it seemed to hold on to a sense of itself. People like me, with grey-flecked beards, will recall a time before these hotels brought a funkier aesthetic to the British market. It wasn't a nice place to be. Bathroom suites were avocado. The Hotel du Vin group changed things for the better.

Now, in what feels like a logical move, it has spun off the bistro side of the business into stand-alone restaurants. There are currently two in London, and doubtless there will be one near you soon. The branch in Soho looks right: there is a zinc-topped bar, cream-painted wood panelling, tasteful antique sketches and empty wine bottles lined up like sentries along the top of the banquettes in the middle of the room. The menu reads well, too – it's a knowing set of bistro classics, from chicken parfait to moules to onglet – and is very much on trend. On the back they list their suppliers in some detail.

It's just such a shame the whole experience is so terribly mediocre. It's not catastrophic. The cooking isn't so bad that you will be left questioning the meaning of existence, which is a pity. Truly hateful experiences at least give you anecdotes with which to entertain the kids. This is just glum, off the mark, and costly for it. Nobody wants to spend £110 on a meal that makes them shrug. The one good dish was a disc of white crabmeat with brown crabmeat on top, and slices of thinly cut toasted sourdough. Deep-fried sweetbreads, however, were a disaster. They had been grotesquely overcooked and were so hard you could have gravelled a path with them. The accompanying charcuterie sauce was over-reduced to a varnish.

An onglet steak was OK, but the chips were limp and dull, and the béarnaise sauce had the over-thickened, gloopy quality of something that had been bought in which, given my legal obligation to assume it was made on site, is a shame. The nicely glazed shortcrust pastry shell on my beef-and-onion pie gave way to a half-empty pot of merely OK filling. Either use a smaller dish or fill it up a bit. Roasted marrow bones had been allowed to cool for too long, and the marrow had started to congeal.

Desserts were gloomy. An apple and blackberry crumble arrived in a scalding hot dish, but was cold in the middle. We sent it back to make a point. The topping was dusty. A strawberry vacherin sundae was a tragic thing of cream, strawberry sorbet, vanilla ice cream and rock-hard dusty little meringues like the toppings to iced gems. With starters at around £7.50 or above and mains well into the teens, none of this is acceptable.

As the name suggests, they do still make a point of the wine. The list is intriguing, if hardly full of bargains, and there's a good selection by the glass. But none of that makes up for a meal which was notable for all the things that were wrong, not for all the things that were right. None of that destroys a memory of a lovely rescued night long before we finally became parents. But it is a major disappointment.

Email Jay at jay.rayner@observer.co.uk or visit theguardian.com/profile/jayrayner for all his reviews in one place. Follow him on Twitter @jayrayner1