Late to the thread, but with an idea...
First off, IANAL and don't know much about employment law, but does the moment the IT Director calling James somehow 'reverse' their argument for that redundancy to have occurred in the first place and given him a credible argument to sue them for wrongful dismissal? As another El Reg commentator mentioned, the moment of being escorted off the building in such circumstances meant that the company should have never called him again, or had legal access to call his number other than admin in dealing with his P45 etc.