While I agree you are not really buying from Bunnings, I would put Aliexpress at the bottom of the list along with Temu. While their prices may be cheaper there is no AU consumer protection. With something like a diesel heater that protection may be important. And the more people who use such sites, the harder it is for the local businesses to survive.

I have purchased from the Marketplace arms of Bunnings and Woolworths and they are typically Aussie sellers, whereas ebay has drifted more and more towards offshore sellers. They are all using the same business model.