CAP296, CAP697 and CAP698 can be downloaded from the UK CAA website in PDF format free of charge. Just go to caa.co.uk and do a search for them.
It is best to have the whole of each book in paper form when doing the course, so that you can highlight key facts. Each CAP contains a lot of information that is very useful in the exams.
You will not be permitted to use your own in the exam. Some people try and some people (not all of them) get caught out when the invigilators take away their marked copies and give them unmarked ones to use.