The questions I feel are most appropriate are these:
1) Do you think you might want to study science in a degree where methods is compulsory? (i.e, anything at Monash not including the BSc [as Indefatigable said below, the normal BSc doesn't require methods]/Global Challenges, or science at Melbourne)
2) Do you think you'd like to continue to do physics after year 12?
If the answer to number 1 is yes, do methods. I think the reason why is pretty self-explanatory.
If the answer to number 2 is yes, do methods. Even if you enrol in the Monash BSc, trying to continue on with physics whilst playing catch-up with your maths abilities is honestly a very scary concept IMO. (plus, I don't even know if they'd let you without begging the unit coordinators...)
However, in terms of scientific understanding in general, being mathematically literate is important. If you cannot understand mathematics, some research papers will be entirely foreign material to you - REGARDLESS of the discipline. (I have seen bio papers and geo papers that I couldn't understand, even with more maths knowledge/experience than the people studying said papers at the time) So, I would suggest not dropping methods.
Of course, if number 2 was a no, I'd suggest keeping methods and dropping physics. A background in physics is nice, sure, but IMO a background in maths is more helpful. If you need to know about physics in your career, you will be working with a physicist.
Finally, your English subjects - if you decide at the end of the day you want to drop one of the English, that's your choice. However, doing an extra English could benefit you in the sciences anyway. Being articulate in reports is something that a lot of scientists are terrible at, and being able to communicate your research is an important part of being a scientist. Honestly, being more articulate in your primary language is a much greater advantage in the scientific community than having year 12 knowledge of a science you don't research in.