In fairness if anything is in soft copy it's almost certainly possible to download it for free once you look hard enough or get someone tech savvy enough to do it for you. I'm not saying it's right or wrong just that it's a free option if you take this route.
Saying that your required to go through a school for your exams so defo worth checking from the horses mouth how using learning materials not purchased through the school will pan out.
Personally I prefer written material and it's proven that folks absorb more information from a book than through a computer screen, forget the figure but it was a largish percentage.
Another route for the ATPLs and one which is very cost effective is to do your ATPLs through CATS, you can get the online material and all your ground school for about £900 then hammer the Bristol Question Bank out of it!!
I went with Bristol, instructors were top notch (ex Virgin, BA, Cathay, RAF) whereas I think in Oxford your just paying for the name, I knew a few lads that taught there who were just out of flight school whereas in Bristol you've got auld fellas with heaps of knowledge, experience and more importantly they were excellent at imparting that knowledge. Again this is just my take on it.
Best of luck with it!
Engine Failure: A condition which occurs when all fuel tanks mysteriously become filled with air