Ann: Greenfield Programme Identifies Havieron Lookalike Anomalies, page-35

Some enlarged images that give a hint of more detail.
Mag 01

As you say Nammuldi a very distinctive anomaly.  Has a bit of strike length and some flexure at this scale.
An ENE trending possible dyke swarm in this and the next image which is not visible in the background older mag survey.

Mag 02

The anomalies to the north look similar but do not have the same peak.    The new survey brings out much more detail on the claim block which may be repeated if such a detail survey were run on the surrounding ground (not AZY's)  The increased detail is not surprising as the parameters of the survey and instrumentation were designed to improve resolution. 

Would this level of surveying be cost effective for the rest of AZY's ground??

Note how the mag detail (=Survey) extends beyond the claim boundary.  This is (in part) a function of gathering data and calibrating the instruments I believe. 
Reading up on airborne gravity (Falcon among others) in papers from the early 2000's, the instrumentation needed some 4 kms to be "stabilized" so going beyond boundaries was required.  
Technology improvements and the use of helicopters and drones rather than fixed wing aircraft will be constantly changing these system issues.


Mag 03 - repeated here to complete the set.



Mag 04 - note survey data/interp? predates 2018 work.