Sorry creamy, but you are wrong. The secretary, deputy secretaries and the younger "clerks" at PM&C are about the brightest this country produces and it would be a very courageous politician who ignored their advice. Ministers are well aware of the powers of PM&C and tread carefully because they have the ear of the Ministers boss.
Of course gillards advisors carry a lot of weight, but when it comes to "managing" other public servants and dealing with administrative matters, the PM&C public servants are the masters. The advisers have a say in policy but the public servants make it happen.
If Gillard believed there was a need for action, PM&C would tell DOT what was going to be done.
Having said all that, the CASA report appears factual, at least to an uneducated PPL like me.