John Blakeley,
To my mind it is quite simple; if I have interpreted what you have said correctly.
1. The Chinook Mk2 was operating on a provisional "Release to Service".
2. Problems arose during the Boscombe Down Trials which lead to the premature cessation of those Trials; but no action was taken by Boscombe Down, MOD or the STC EA to suspend or amend the provisional "Release to Service" under which the Chinook Mk2 was operated.
3. No action was taken by those Agencies to ensure that HQ 1 Gp was immediately notified of the cessation of Chinook Mk2 trials (and the reason for that decision) prior to the tragedy of 2 June 1994?
4. None of the above absolves the Flight Deck crew of ZD 576 of their responsibility to operate the aircraft in accordance with Military Flying Regulations, Air Staff Instructions and Group Air Staff Orders extant at the time.