Currawong,
From your last post I am not too sure if this a hypothetical question based on a mythical document OR a true question based on the actual document.
In any case, any report made to the regulator is made in confidence, it is not broadcast nor published/printed by the person initiating the report nor the regulator to others so as to cause injury to the reputation of the person named therein.
So, no .. it is not defamatory, in that sense.