The answer, very clearly, is that the call for “new” evidence was answered.
And that new evidence was CHART and airworthines. But that was a road that MoD did not want to go down. It would implicate the RAF Chief Engineer of the time, and make Haddon Cave, and his "golden period" look foolish. So they elected to give up their long held objection to the the legal issue and clear the pilots that way.
I agree with the points that Walter makes, and MOD ppruners should understand that the airworthiness issue will not go away, until all those who failed to act on CHART and NART are named and held accountable.
DV