FWIW ...
Very simply put, a CREDIBLE audit (for as much as this does exist) is one that is performed by an IDENTIFIED auditing firm that has a reputation that can be verified.
I think I iniitiated the use of term CREDIBLE following a presumed audit that would have been done over a year ago by a named firm no one was able to ever find. I kept using the term after Anne Tahim put a disclaimer on her report saying that she didn't even know (or at least did not name) who audited the numbers from Bingladesh (over 95% of the claimed revenues) which were just handed to her.
Note: I ended up finding out who presumably audited the Bingladesh numbers and found that the said auditor wasn't reliable. I however gave my word that I would not divulge this information and I did not, nor to I plan to. This however is water under the bridge but that's also what I refer to, using the term credible.