So, I had the advisor from seek call me back.
When I let him know my decision, that I'd decided to go ahead and do the cert 4 (through tafe, not seek) he asked if I'd done the 3 yet. I said no & he went on to say that I may not be able to do the cert 4 as I haven't done the basics of cert 3.

Way to make me feel stupid. When I first got in contact, it was the cert 3 I was signing up for. HE was the one who thought I'd be better off doing either the cert 4, or even trying the diploma. Sigh. I'm hoping it was just because I turned him down?