Credit to Gaz1 for mentioning this deal.
Unlock @ Fonefunshop for 3 pounds. Using 28Degrees Mastercard it converted to AU $5.74.
I have this phone and it works on Kogan Mobile without unlocking. I have since unlocked it using the link above.
Currently sitting in 2nd place on Ozbargain's Best Budget Smartphone (Under $300) in 2019