I think you are all missing the point completely.
The reason there is an investigation and directions from CASA is because QANTAS DOES'NT KNOW who is qualified for what, and what they have signed for. It's cut so far that it has started losing part of its organisational memory, and that is why this situation, whatever it is, was allowed to develop.
That is the issue, QANTAS DOES NOT KNOW! Now the reason I've bolded and capitalised that statement, is that Qantas, as an airline operator, is supposed to have systems in place to guarantee the quality of it's maintenance and overhaul work, and that extends from your licences right down to the calibration of various tools, let alone traceability etc.
To put it another way, the fact that the issue, whatever it is, could potentially involve work over Two years old means that QF have no effing idea.
The obvious question CASA should be asking is "What else is there that Qantas should know, but does'nt know?"
And for good measure, the reason Ansett's AOC was pulled was not because of a crack, but because investigations determined that AN's maintenance system could not guarantee that the minimum required work was being done - and for the same reason - cut costs and fire people - lose organisational memory.