London is not officially a coastal city. But the steady creep of urban sprawl, plus inexorably expensive housing, improving train connections and the stubborn persistence of home working mean certain choice seaside outposts are becoming, if not absorbed into the capital, then arty, bohemian satellites of it.Forget Whitstable, Deal and Aldeburgh though — too established with house prices to match. The new London-on-seas are edgier and more affordable for the steady stream of disaffected creatives seeking sea air and a new lifestyle — with good wine and nice coffee close at hand.