you definately dont need to do 1+2 general Maths in order to do Further. If your school is that stubborn, try to get your parents involved (works like a charm) and if they still dont let you, do it by distance. Further, I dont think needs explanations, its pretty straight forward, though if you need help im sure if you post it here, somebody will get back to you.
You could also tell the school that if they're not letting you do it, you'll do it by distance, which costs $500 extra, so I would use that $500 as an excuse. If they're only problem is that you have too much to catch up on *sigh* and you are determined to do it, then im sure they'll let you.. I dont see any reason why they wouldn't.
But im sure getting parents involved would work, had a friend who done spec without 1+2 general maths advanced, and persuaded the school to do spec in yr12 while doing further in yr11 instead of gma.
LOL that was my further maths experience..sitting there...doing english homework.
I was doing my methods..
