My world record for a redacted document was a 2,700-page one. I got lovely new sheets of paper to put into my fax machine at the time.
I would say that it probably does best in empowering the Information Commissioner to have greater oversight and, if necessary, to then have a small agency, a small board or a small adjunct to the Information Commissioner's office in order to help arbitrate redactions so that the public interest is served better.