They’re accused of trying to manipulate elections across the world, they’re different, they’re aloof, they’re under concerted political attack and they don’t like talking to the media. All the right reasons, then, for Investigate to persuade the businessmen involved to front up on where their money came from, why private eyes were hired, who authorized  the move against Labour and whether, given the chance again, they’d do it differently. IAN WISHART has the story