AS ONE door opens, another closes. In other Whitehall departments jittery hordes of special advisers are reported to be passing their CVs to headhunters and recruitment agents in fear of their careers coming to a sudden end at the next election. According to industry insiders, they are making inquiries about jobs in public relations and consultancies. Some fear the rumoured September reshuffle could prove a career-changing moment for them even earlier. The problem is, in a changing political climate, the top agencies are now casting round for potential staff with Tory rather than Labour links.