I moved from Malaysia to UK in 2015, so basically I came here during the time A-level newly reformed. I didn't find the learning differ much from both countries. Though it really helps if you've somewhat done the same level of study in whatever country you are moving from. For example, before I left for A-levels in the UK, I was doing a foundation at university with the same subjects as the one I chose for A-levels, Maths and the triple sciences. These are global subjects and the stuff you learn at each level doesnt differ much, as long as they are in equivalence and it helps if the country you moved to in Asia is under commonwealth, as they typically would follow the british education system. For the exams, if you're willing to pay the fees, then I dont think you have to go to the classes personally. It's just that colleges are typically subsidised for the exam fees, so they expect students to do well in them, that's why you have to go to college