Quest Specialist Maths to get you going. Great textbook to use over the summer holidays. then after finishing with that textbook you should move on to something more difficult like Essentials.
x2 textbook for maths subjects is recommended at our school. but i don't see the point. practicing exam-style questions is more worthwhile imo. Some textbooks don't offer that aspect of questions. The downside to essential specialist maths is that their analysis questions are not a multi-stage solutions of increasing complexity but the question is in a whole paragraph form which makes it very difficult to comprehend. I guess thats the case for most text books.
If you have to choose between Quest and Essential, it really depends what your school uses, and your level of mathematics. If you are aiming 40+ ss raw, then I think Quest is not suitable for you.
Never did accounting so I dunno. but i heard A+ accounting is shit.
Chemistry. I used heinmann. my personal preference for textbooks is that they need to be colorful and nice to read. because you don't want to read a textbook which is black/white and have no pictures. and especially in chemistry, you have to read a decent amount. you would want to occasionally look at pics/graphs for further explanations, rather than paragraphs.