If the AVMs were responding to a political directive then you are not going to get a change arguing over just legal technicalities without understanding the nature of any such directive – particularly, who originated it.
I'd bet there would be very little chance of getting that – they can't even identify (the particular individual) who made the decision to use the Chinook.
However, if it could be determined that the flight had some other activity that had not thusfar been declared then the verdict would surely be untenable.
There are just too many anomalies on this flight for it to have been merely a ferry flight – why don't you (collectively) who have exercised in that area put your heads together (in private if necessary) to consider this possibility?