Lefty. Your Ops Manual is a document (or rather, a series of documents) that CASA signs-off on as your operating procedures that govern exactly how CASA will expect you will conduct business and operate your aircraft and oversee your aircrew. Part of your AOC requirements are that you operate solely within the envelope of your Ops Manual, as its very approval is the only guarantee that CASA has that your operation knows exactly how to operate legally, or at least in a manner that CASA approves of. If it is in your Manual that CASA has signed-off, then it is reasonable to expect CASA to expect you to comply with your own manual.
Unfortunately, that makes it another stick that can be used against you.
I cannot remember reading anywhere that it is a requirement to sign your licence upon reciept to make it any more valid either?
(edited to read more like what I was trying to say)
Regards,
OpsN.