I'm a bit confused with the various opinions above. Having read the discussion, I went and read the report from end to end and I have to say that it seems the AAIB did a reasonable job:
They investigated the facts and arrived at a probable cause for the accident. They then looked a little wider to investigate the circumstances that led to the defects in the accident aircraft. Surely, that is their job?
I didn't interpret the contents of the report as a damning indictment of the BMAA's processes (even the recommendations are that some of the procedures be reviewed, not that they be scrapped).
However, since the investigation points quite convincingly to a structural failure, of which one major causal factor was the failure to carry out an AD correctly (and not to subsequently spot the error), it does seem reasonble to attempt to recommend actions that may prevent the same thing happening in future.
As a PPL(A), it does concern me that whilst a trial lesson in a light aircraft would require a public transport CofA, the same thing in a microlight could be done in an aircraft that had at best a sketchy maintenance history. It's also worrying that there is no clear procedure for an inspector to be assessed as competant to do their work.
Back to the report, even the paragraphs hinting at a minority that resent interference by the CAA are written carefully, using the word 'inadvertently' and pointing out that the minority referred to might actually be competant to question certain regulations but that this might have caused others to be caught up in an air of anti-regulation without that competence and understanding.
However, given all that, if this report is actually being used by some to blame the inspector for this accident then that is also wrong since it's absolutely clear from the report that there was a long chain of events here (as in almost all air accidents).
I would also concede that only some of the report's recommendations are actually relevant to the actual accident (but arguably all do have safety implications).
Mark