Wikipedia gets a bad rep but it can be very useful for reading around parts of your course, such as certain events. I wouldn't rely on it but it can be quite helpful. I don't do AQA but it sounds like a good idea to use books that are designed for your exam board as they should cover the topics you need to study, even if it isn't in complete detail. The most useful part of those kind of books is the exam tips they give you, things such as example answers, and questions etc.
History A-level has a lot of content so I would advise on using both to help you compile a solid set of notes. You should really go beyond this and do plenty of extra reading to help you understand everything, but obviously don't go about trying to study everything you can find as this won't help you!
I hope this helps, good luck with your course! I hope you work hard!