Just an update - my unit was running firmware from 2018. Slow, sluggish, terrible. After installing the supplied firmware to get me to 4.22, I also managed to use the firmware 'supplied' by my local supplier. Was expecting more AU firmware, but was simply pointed here:
Video recorders
So apparently using 'US' firmware on my 'AU' unit was fine. And it worked. Upgraded to 4.40 I think. No problems. NVR running smoother than ever. The 'pulsing' issue I have is less prevalent on medium quality continuous recording. I can also use H265 now without the unit eventually becoming sluggish/crashing. Huge boon for space savings!
And the one thing that
really bothered me was selecting existing footage from the review section. Selected one camera on old firmware, and it would take close to ~30 seconds for it to appear in a window on its own. Since updating to later firmware, I can select cameras and their recorded footage appears almost immediately.
And I got my 'shape drawing' login back that I had on my old NVR, bonus! The only 'issue' I can see now is that while my Seagate SKyHawk is recognised as a usable HDD, my WD Purple 3TB unit isn't recognised as an 'approved' HDD (still works though).