Earl Spencer plainly is a forgiving man. For his latest divorce, his third, from Karen Gordon, he’s hired Fiona Shackleton, the legendary divorce lawyer who acted for Prince Charles (as was) in his sister Diana’s divorce. No matter. Lady Shackleton — the lucrativeness of whose speciality can be seen in her title, of Belgravia — is the lawyer of choice for celebrities looking to come out of their difficult marriages with their dignity and assets more or less intact.