I have visited the restaurant twice now – once as part of a visit to the Gallery, and once for dinner. Both meals were excellent, with all the dishes we tried from the short-ish menu being beautifully presented, bang up to date seasonally, and terrifically tasty. Our favourites were the bream and the wild garlic & leek soup, though the textures of heritage carrots is a wonderful dish that I would choose again as a main course even though I'm not veggie.
Of the two visits, I'd recommend going in the evening, when the atmosphere is cosier, and the contrast of the sleek restaurant design with the somewhat unloved street scene outside is starker.