Update 1/4/21 3.15pm AEST.
After correspondence with NSW Spatial Services today, they have promptly acted to rectify this issue. The https://six.nsw.gov.au/etopo
catalogue has now changed back to the 2017 series which features georeferencing.
Spatial Services have advised that the 2017 maps are now online at https://six.nsw.gov.au/etopo
. The 2017 version should work as intended with common phone nav apps such as Oruxmaps and Avenza.
If you have a 2020 series map you may wish to delete it and download the 2017 series in time for your next walk. This series is identified by 2017 on the cover.
Thank you to NSW Spatial Services for their very quick response and action.
Edit. Changed to seperate post so the update appears in active topics.