There is no such thing as a low level endorsement. Nor can AG pilots conduct low level operations other than ag ops unless they complete a flight test. See CAO 29.10.8.1 and 9.1
CASA accept training for low level ops iaw the Syllabus in paras 1 and 2 (aeroplane) or 3 (helicopter) in Appendix 1 to CAO 20.10.
Most AOC holders should have a syllabus in their OM. This syllabus should be iaw the Syllabus in paras 1 and 2 or 3 in Appendix 1 to CAO 20.10.
Student helicopter pilots do get periods of low flying training but this training is iaw the Day VFR Syllabus.
It is a very grey area that really needs rectifying.