One billionaire’s frustration can be another’s opportunity. After the Norwegian-born shipping baron John Fredriksen quit London, he declared “Britain has gone to hell”, but his departure has created the chance for someone to snap up his home. They’ll just need to have at least £250 million to spare to buy one of the capital’s most intriguing and desirable residences. Rather than merely shutter the Old Rectory, the 300-year-old Georgian manor, or hand it to one of his two daughters, Fredriksen,