of course you can do ATPL studies, I'm not sure if you can sit any exams mind or if all schools will take you. However, there is nothing stopping you doing the ground study, you can get books through CAE or through BGS. If you're bored get them, read them and understand them, do some of the questions and you'll only be going on to help yourself in the long run. If you wanted to do the mock exams you can do that too through AE or BGS I believe. If you want to study, there is nothing to stop you, and if you do it will help you long term.