The Roof Garden is a pale, Nordic-style restaurant at the top of the glorious Pantechnicon in Belgravia — formerly a bazaar — opposite a Waitrose I didn’t know existed. (Waitrose seems too human for Belgravia. Food seems too human for Belgravia.) This thrilling building, which should be a library — it has Doric columns — is instead a collection of restaurants, shops and what I think are called ‘outlets’ (a Japanese café; something called, gnomically, ‘Kiosk’), all celebrating the ‘playful’ intersection — I mean meeting, but marketing jargon is addictive if you are an idiot — between Nordic and Japanese...