I think the point Chug makes is self-regulation is fine so long as one implements the regs properly. MoD has admitted it doesn't, a simple verifiable fact.
As Tuc says, whether you've implemented the regs or not is the key issue, hence:
The point isn't the discharge of responsibilities by particular organisations or individuals
...well, you could argue it is really. That is the whole point, and furthermore you need to question whether the regs you did/did not follow were adequate to have caught the underlying problem in any case or whether a new facet of regulation is needed (e.g. years ago failure to properly consider Human Factors during design & risk analysis).
You cite problems
concerning the Nimrod, Hercules and Chinook fleets and the serious Airworthiness shortcomings revealed
Nimrod, potentially yes, but why Hercules & Chinook? The Hercules was shot down - a military risk/threat decision was made long ago not to bother with some technologies which may or may not have had any effect in any case. This is not really an airworthiness issue in the traditional sense, as bad guys firing bullets/rockets at you is always going to be a dangerous situation with risks that cannot be fully mitigated. The Chinook was regrettably, but almost certainly (but not perhaps beyond all doubt due to lack of much evidence) flown into the Mull by its pilots. The MAR/FADEC issue was a red herring.
Be careful not to lump together and confuse different complex issues.