The first things should be (a) any criminal prosecutions against the Post Office and/or Fujitsu and/or members of staff responsible...
OK; IANAL but IMHO the Post Office & if appropriate Fujistu should be on the receiving end of a criminal prosecution for Malicious Prosecution, and the responsible individuals (as opposed to the bodies corporate) be on the receiving end of appropriate punishments.
The prosecution of the sub - postmasters was pursued in the face of mounting evidence that something was wrong with Horizon but they pressed on regardless, even to the point of shutting down a formal enquiry that they themselves instigated when it was becoming obvious that the findings were turning out to be unfavourable to their case and even trying to get the trial judge to recuse himself because he seems to have spotted what was going on.
Paula Vennells CBE "for services to the Post Office" should be put under immediate review because she headed up a course of action that actually brought the Post Office into serious disrepute.
The government is the PO's sole shareholder and I have a strong suspicion that its proposed "review" is intended to prevent any serious investigation into the action that was taken, not facilitate it. At the same time, of course, it is allowing soldiers who served in NI during the troubles to be harried for events that took place 40 years ago with prosecutions being a distinct possibility as a result.
The sub - postmasters deserve better than this; in fact we all do. Much better.