Kogan 4K HDR TVs - 43" [$499], 55" [$549], 65" [$899] @ Dick Smith
Dick Smith (now owned and operated by Kogan) have a range of very cheap 4K HDR TVs on offer.
Regarding duty - the Dick Smith website says: "The vast majority of our products incur no additional costs for duties or taxes - the price on the website is the final price. In the rare instance additional duties are required, you will be notified at checkout." I have checked the 65" television by adding to my cart and continuing to checkout, and it does not incur an additional duty.
A 65" TV at $899 with shipping of $112 comes in about $500 cheaper than comparable products at local retailers.