Week-by-week, I'll build up this page with more revision materials for you to try. Agile development in action! .
Parsons problems
Rearrange the pseudocode or code for the key algos that you need for your A-level CompSci. Then code them yourself, or apply them on a dummy set of data. Great prep for module 2.
Knowledge terminology quizzes
Learn all the key terms. These self mark (imperfectly), but you must start each answer with a capital letter. Revisit the quizzes after a bit of a gap over time until you are scoring highly in the run-up to exams.
Codingbat.com is for levelling up in Python and Java. Simple but properly free with no gimmicks.
Leetcode.com is great to challenge yourself and to prepare for interviews etc. It forces you down the OOP route, which seems a bit weird for python sometimes. It also encourages codegolf and over-optimisation, leading to a lot of horrible answers!
Codewars.com is gimmicky in the extreme but challenging, addictive and with an active community. Takes a while to get into it.