You can get your ETA (Electronic Travel Authority) instantly and on line. No need to go to the high commission (Commonwealth countries don’t have Embassies with each other - they’re High Commissions) or do it through a 3rd party.
Nitpick: England is part of the United Kingdom; it is not, in and of itself, a country which issues visas.
My oddest visa experience was for Denmark. I was visiting the University of Aarhus for a month and getting a month’s pay. I knew I needed some sort of work permit and went to the Danish consulate with my letter of invitation. The consular officer said sure and put a big stamp in my passport. I looked at it and it clearly said (in English), must not take up any work. I pointed this out to the consular official and he said, “No problem” and took a ruler and his ballpoint and drew a large X through the offending paragraph! No one actually ever looked at the visa. This would not have worked in Canada where the payroll office insists on seeing the visa. (Americans, but not others, can get a one year work permit at point of entry.)
I am well versed in how one obtains an ETA, having processed them for many clients. As a citizen of the Commonwealth, I am aware that all of our monarchist co-states have High Commissions in Ottawa, as well as consulates in other cities. It was a simplification.
It’s still $20.00 AUD, as per the Ozians themselves, online or in person. A good travel agent or airline will process it for you and eat the cost.
Also, any airline that lets a passenger board without the proper documentation deserves the fine and the cost of shipping the clueless one back home.
precision matters - you said it must be done at the embassy/high commission or done through a travel agent. which is incorrect. and it’s not just the monarchist co-states, either.