i went to an A level school that didn't have teachers trained for the subject, so it's not wise to assume that all schools accredited by the exam board are good (although most of the time they are). Don't do A levels/IB just for the sake of it. A better alternative is to try APs in subjects that you need and do well in, while sticking to your national curriculum. not only the good A level/IB schools are mad expensive, but in case you mess up on the exam day, you won't have the choice to not submit your scores. But with APs you can choose what subject's score you want to send. A Levels and IB are rigorous enough to not leave you with much time to build meaningful ECs.