Reviews: Marina O'Loughlin is delighted by the 'pleasingly bonkers' Mo Diner, while Jay Rayner says Elder is 'a brilliant beam of sunshine'

The Sunday Times' Marina O'Loughlin is delighted by the "pleasingly bonkers" Mo Diner in London's Mayfair, the latest venture from Mourad Mazouz, with Éric Chavot at the helm in the kitchen

This time Mazouz's restless vision has delivered a homage to the classic American diner, raised stools fringing the galley kitchen, luncheonette-style pegboard menus on high. But one reimagined by the designers behind Elvis's more excessive, pigment-soaked movies after a week on the Maui Wowie: the ceiling is backlit palm trees, the colour scheme egg yolk and aubergine with touches of modernist wood panelling and almost art deco glass. Tiles glitter with a golden shimmer.

When food starts arriving it becomes rapidly obvious where the seriousness lies. The flavours are all over the place: French/Mediterranean ("Mo bouillabaisse", mussels with persillade and garlic butter; Provençale-style socca – chickpea pancakes); the Maghreb ("1,000 holes Moroccan pancakes"; shakshuka, but with Balearic-style sobressada – their spelling; harira soup; "Stephane's mum brick", the Berber pastry dish, sadly unavailable on our visit); the whole thing given a bit of a sun-soaked, hard shakes-fuelled LA razzle-dazzle. Even breads are ecumenical – spongy cornbread, herb-flecked focaccia, sourdough, all first-class.

There's no point in looking for a coherent narrative, there isn't one: this is a menu where tinned sardines jostle with full English breakfast. But it's all so good. Falafel, emerald inside from courgettes, are the fluffiest little savoury doughnuts, a drizzle of tahini-lemon tarator sauce soaking through crunchy exteriors to create simple luxury. Confit duck – very much Chavot territory – brings a stellar example, the skin papery crisp, sour-sweet from pomegranate molasses, meat almost leaping off the bone. Fat, fresh prawns come with overcoats of Weetabixy shreds of crisp "kadaif" pastry and a saffron aïoli for plush richness.

And I can't remember the last time I waxed evangelical about a salad, but carrot, toasted almonds, tiny dots of lemon and orange flesh and quantities of mint and flat-leaf parsley is so hedonistic that the word "salad" doesn't do it justice.

Price: meal for three, including 13% service charge, £156.50

Jay Rayner of The Observer describes Elder, the restaurant at the newly opened Indigo hotel in Bath, as "a brilliant beam of sunshine breaking through a bruising, cloud-deadened sky"

Here's Mike Robinson, the chef renowned for his game cookery; for dishes involving words like haunch and faggot and shin, opening a new restaurant into the gnashing teeth of a pandemic. It's surely madness. If so, it's welcome madness, a giddy expression of optimism.

Among the starters is a warm crab tart, which has me blinking and grinning and hunting around for useful comparisons. Let's try this. It's the Judi Dench of crab tarts: classy, technically brilliant, compelling but also moving and hugely satisfying. There's a layer of white crab meat and a layer of the brown meat for punch and, on top of that, a brassic, hot and sour chimichurri, like a neatly mown lawn. It's that rare thing: immense precision in the interests of appetite.

There's a lot going on with the mains. too: a partridge breast partners a ball of stuffed savoy cabbage and a sweetcorn tart with black pudding; deep pink venison comes with red cabbage purée and beetroot, and so on. Both have intense sauces. Bravo. But I'm distracted by a side dish of what they call "dirty mash". It's a pot of Joël Robuchon-style pommes purée, as much butter as potato, flooded with a copious amount of a reduced venison jus bobbing with shards and tangles of meat.

Price: three dinner courses, £45, three lunch courses, £35; wines, from £25

The Guardian's Grace Dent declares the restaurant, wine shop and deli Fourth and Church in Hove, East Sussex, to be one of the greatest eateries she has visited in recent years

This is a small, independent labour of love – imaginative small plates, dizzying wine line, fabulous service – that I found out about only after several of its regulars got in touch feeling rather rattled that Sam Pryor and Paul Morgan's neighbourhood joint was being ignored.

"OK, I'll pop by for a few plates," I thought, expecting something perfunctory and ending up with egg all over my stupid face because the place is joyous. Confit duck beignets with a puddle of piquillo pepper ketchup, to munch with your first, very good martini. I dream of Pryor's crunchy fried chicken thighs in breadcrumb with kimchi rémoulade, and his trout cured with pastrami-style seasoning and arranged prettily on crisp bread with pickled onion and cream cheese.

Fourth and Church is an example of why we will always need restaurants, no matter what, because I love to be at the absolute mercy of such flights of culinary fancy. Warm lamb shoulder croquettes arrive with pickled quince and rosemary-infused aïoli, while mackerel is served on freshly made blue corn tacos with pickled jalapeños and a heavenly marjoram slaw. Charles wittered on for days about his grilled duck heart brochettes, which came with wilted greens festooned in an earthy, pistachio-based slant on dukkah.

Price: tasting menu, £40 per person

All restaurants were visited before the new national restrictions were announced last week.