Some AU postcodes not returning results

website: https://cambridgeweightplan.com.au/find-a-consultant/

Installed:
GeoDirectory V 1.6.25
GeoDirectory Location Manager V 1.5.62
GeoDirectory Advance Search Filters V 1.4.92
GeoDirectory Marker Cluster v 1.3
GeoDirectory Custom Post Types V 1.3.6

The directory seems to be “missing” some AU postcodes and then searches for a geo location, bang in the middle of Australia (in the desert!).
https://cambridgeweightplan.com.au/?geodir_search=1&stype=gd_consultant&s=+&snear=2019&sgeo_lat=-25.274398&sgeo_lon=133.77513599999997

Some examples of problems:
Sydney postcode 2000 (but can be found if you just enter “Sydney”)
Botany postcode 2019 (but can be found if you just enter “Botany”)

And several others around the Sydney area e.g. 2020, 2006
ALL of these are generating a query string with the above Lat/long measurements (central AU) and do not give the same results as when you enter the suburb directly.

Radius is set to 100km

Many other postcodes do not have a problem e.g. 2216, 2207, 3000 and many more, all return results.

I tried setting “Add location specific text to (Near) search for Google” to Australia after reading another post about postcodes that were duplicated in other countries but it made no difference. Still no results were received, so I have now removed that entry.

Please advise.

Janet