I work for a company called Seneca Learning, which has created a free GCSE revision & homework platform. It is exam-board specific with content written by senior examiners, and applies neuroscience to enhance understanding and memory. When tested on 1,120 students, those using Seneca's platform performed 2x better than students using revision guides & textbooks to revise. You can find it at https://senecalearning.com/ . It's free!