I wouldn't bother trying to 'predict' your study score for English. There are far more important things to concentrate on than speculating over what marks you need to get a certain score. The danger in asking these questions is that you fall into the 'good enough' mode and end up not doing the best you can because you've convinced yourself you only need a certain mark to get the study score you want. Your main focus should be striving to do the best you can, rather than trying to quantify how much effort you should put into the exams.
Another problem is that predicting study scores, especially in English, is a very speculative exercise. 50% of your marks come from SACs which get moderated. I don't think anyone fully understands the moderation process for SAC marks, but it is clear that people can do surprisingly well despite not having the best SAC marks so long as they are strong in the exam.
Making a tentative assumption that you only need to get 'X' on your exam does not really help you. Its easy to get distracted with these sorts of questions when really you could spend this time studying instead.