It's been a while since you posted and nobody's replied yet...maybe you should check out MarkedbyTeachers.com, TSR's sister site. It has the largest library of essays in the UK.
They've got over 181,000+ coursework, essays, homeworks etc.. all written by GCSE, A Level, University and IB students across all topics. You get access either by publishing some of your own work, or paying £4.99 for a month's access. Both ways give you unlimited access to all of the essays.
All their documents are submitted to Turnitin anti-plagiarism software, so it can't be misused, and the site's used by hundreds of thousands of UK teachers and students.
I don't know how much this will help you because I didn't sit these subjects when I did my A-Levels, but this more general revision help so hopefully you'll find it useful!
You don't need to be searching specifically for AS revision, when I was doing my history A Level my topics were Nazi Germany and Communism in Russia and I just used standard history books as opposed to A level specific ones. As long as you are looking at subjects which you have been taught and not wandering off into areas that aren't included on your course it can actually be more helpful than an AS text book. Try using google books it's easy to use and you get access to thousands of books, it's been the most helpful thing for me in my degree! Or try googling key words from your topics to find webpages which offer information on your topics.
Hope this helps! If you struggle to find anything give me an example of a specific date or topic from one of your modules and I'll try to show you how to find stuff