Mt. Koscuiszko is the highest mountain on MAINLAND Australia (as I said already), but it is NOT - I repeat, NOT - the highest mountain of my country.
Yes it is. You said so yourself:
Another surpassing Mount Koscuiszko [sic] is Mawson's Peak on Heard Island, which is 2745 metres high and forms the summit of an active volcano called Big Ben.
Indeed, your quote states that Mawson's Peak forms the summit of an active volcano called Big Ben. It is not a mountain. It is a peak on a volcano called Big Ben.
Mount Kosciuszko on the other hand is a mountain outright. It is not a volcano nor is it a peak on a volcano with a different name.
Thanks again for helping to reinforce the fact which I've been stating all along and which the Australian government proudly recognizes: Mount Kosciuszko is the highest mountain in all of Australia and therefore is also seen as the highest peak in and of itself in all of Australia.
The geography in these other unrecognized "external territories" is not relevant to the discussion.
The Australian Antarctic Territory might be debatable from a legal perspective (the government of Australia doesn't care, though), but Heard Island is not. That island is unquestionable part of Australia.
I've already told you several times now that virtually no one in the international community recognizes territorial claims to the Antarctic even if those making the claims don't care what the rest of the international community thinks.
Heard Island is an uninhabited nature preserve over 4,000 KM southwest of Australia; it's a wild stretch of the imagination for you to say it is "your country". You never set foot on it and you never will.
Your outlandish beliefs are even more far flung and questionable than these same "external territories" you keep trying to introduce into this thread. It is abundantly clear that you resent the fact that Australia's highest mountain was named after a Pole and by another Pole.
what did you find the same or very similar
Both Poles and the British are proud to show off their shared affinity for royalty: