The mega-rich are best housed behind high fences, on wooded estates patrolled by dogs; that way, they don’t have to annoy the rest of us. But I can see how irritating it must be, if you live in the crowded Ladbroke Grove area of west London, to have a neighbour like Reade Griffith, an American hedge-fund manager who has received planning permission for a vast basement extension to his house that will take many months to excavate.