I did English Language by distance without doing 1/2 and got 46. It is possible to do well. However, you need to be really well organised and strict with yourself to keep up with the work. A lot of people got behind with the worksets. My advice would be to make sure you stay current because the SAC topics are covered in the worksets. If you haven't done the work on an area by the time of the SAC, it would hard to do well. Also, the end of semester rush to complete work was pretty brutal for some people. Imagine doing 5/6 weeks of work in a few days.
I wouldn't worry about not doing 1/2, as long as you're comfortable with linguistic jargon and brush up on the terms at the start of the year, it should be fine.
Anyway, I really recommend studying English Language, it's a great subject.