Translation:I want to go to university in Australia.
The literal translation of this sentence appears to be "I would like to go to Australia to attend college." I think this answer should be accepted.
Ditto for "I would like to attend college in Australia."
The official answer is also grammatically incorrect. It should read "I want to go to a university in Australia." The grammatically correct version is rejected.
Having been here in Australia for over a year now, I can definitely say that "go to university," without the article "a," is a very common way to express that sentiment. I don't see why it should be grammatically incorrect, especially since we use "go to college" rather than "go to a college" in North American English.
Also, fun fact, "college" in Australia (and I assume the UK but I'm not sure) is a school for secondary education (like a high school) and not higher education as would be implied in the USA.
Did not accept "college" for 大学. Yet, the very next sentence I'm asked to translate is "Which college would you like to attend?" and the translation for "college" is 大学.
As far as I know, most people use 澳洲 because it is shorter to both say and write. I am pretty sure they are both correct in any circumstance. Possibly, if you are referring to Australia as a continent rather than a country, you may have to use 澳洲, but I am not positive on that.