Obviously the opinion of a reputable QC would be helpful, but I suspct Hoon offers Judicial Review (JR) as a way forward as he knows it is a complete non-starter from our side.
Any Judge would be bound by the Wednesbury 'Unreasonableness' principle in JR proceedings, which basically means the judge could only overturn an administrative decision by the Govt (such as the Reviewing Officers' Bof I finding) if we could show that no reasonable person could have made that decision. In practice this is a very difficult thing to do, and in laymans terms, we would have to prove positively that only a complete imbecile smacked out of his face on narcotics could have made the decision complained of.
However wrong Day and Wratten have been, it is almost impossible to show that their finding is 'unreasonable' to the extent required by Wednesbury and the JR procedure.
I suspect the only way out now is if both Houses recognise this for what it is - a test of the accountability of the executive to Parliament.
AFAIK, Parliament in our democracy is supposed to be sovereign, and if both Houses were to reject the MoD's response, we could take it that reputations were restored.