The easiest thing to do is to get a State ID. This can be easily done at a local MVD.
Another option would be to get a Driver License. Since you're from Australia*, you will need to get a car (either from a friend or rented) and take a computer and road test.
For either option, I recommend getting an ID valid for Federal Identification (air travel).
For anyone curious, I discovered that Australia and UK have a Double Taxation Treaty that allows for this kind of thing so long as you're only staying less than 183 days for a calendar year and/or tax year.
There are a few exceptions here and there, but article 14 (details 1 and 2 combined ...
If you include only the bachelor's study, you will show you've done only 1 year of study. That's less than the 2 years required for the visa.
If you include only the master's, you will show only 1.5 years of study. That's also less than the 2 years required for the visa.
Thus, if you want to meet the visa requirement, you should include both courses of ...