The restaurant at the heart of the Sheraton Park Tower is a Knightsbridge redoubt of all things maritime. In case you hadn't twigged, the place is designed to resemble the pure symmetry of a shucked oyster, with the seafood counter representing the pearl at its centre. It's an unlikely location for what turns out to be as bracing and exhilarating a proposition as anything on the Brittany coast. You can fill in the sea view in your imagination. Imagination is certainly at work in the kitchen. Pascal Proyart is, among other things, a brand ambassador for the Norwegian Seafood Council, so his commitment to this genre has an ethical as well as gastronomic motivation. It's all good: smoked salmon rolls stuffed with red king crab, served with guacamole and citrus salad, a brace of seared scallops on truffled polenta with rocket foam, cumin-crusted halibut on borlotti cassoulet with carrot purée and ink-dyed cuttlefish tagliatelle. Careful timing and depth of flavour ring through loud and clear, as indeed they do in the non-marine dishes, perhaps chicken breast roasted in Parma ham, accompanied by a coronet of pasta containing black olives, tapenade and asparagus. Dessert may be lemon and black fig délice with fig sorbet, and there are fine cheeses too, served with membrillo and salad.