Perpetually buzzy Olivo is a confident stalwart of Belgravia’s restaurant scene and part of a steadily expanding Sardinian specialist group. It exudes warmth even on a drizzly day, thanks to deep yellow and aquamarine walls and light wood furniture. Terracotta pots and lightshades convey rusticity, while the Italian chatter of the staff leaves you in no doubt that this place is steeped in the food and wine culture of southern Italy. The house aperitif of sherried Oristano-style vernaccia is as good an introduction as any to the sun-baked flavours on offer; peppery olive oil and crisp sheets of Sardinian pane carasau quickly build on the authentic impression. While simply presented vitello tonnato could have come from anywhere in Italy, buffalo ricotta on grilled aubergine was distinctly southern, and a rich, generous plate of mascarpone-sauced pasta with ham would have sated a Sardinian shepherd from dawn to dusk. Hunks of grilled meat chased off any shadow of a hunger pang; happily, yoghurt ice with bitter honey allowed a lighter note to finish. While the prices of the carte are decidedly unbucolic, set lunch is a fair deal, and excellent Sardinian wines (or even Sardinian beer and mineral water) round off a satisfying experience.