It sounds as though the problem of the well-to-do being the slow-to-pay as well is pretty widespread.
I've never had to resort to court action or anything like that, but from talks with people who have gone that route I understand that they've often come away wishing they'd never bothered.
I think the small claims system in England now covers debts up to around £750 or thereabouts. Anything over that, and it becomes a lot more difficult and expensive, with no guarantee that they'll get anything back at the end of it.