I find it very overstated often on this website how much work Extension English 1 is.
I found English Ext 1 to be far, far less work than Advanced and EE2. Other than subjects that required consistent work during the year, I really only had to do stuff at assessment times.
But of course, it depends on your natural aptitude to English and the marks you want. What other subs do you do?
If you want to do well, it's a lot of work and a lot of writing. That's just my take on it.
It differs from adv eng because the questions are a lot more predictable, especially for sci-fi.