Yes you do. To put it bluntly, if you’re doing any of the sciences or maths..Get started now!! You will regret not doing anything in the summer and do you try and take some breaks but use your time wisely in the summer. I was a straight 9 Student at GCSE and I chose biochem in maths but now I’m getting DDD. You will not understand how big the jump from GCSE to A-level until you reach your first week, please try and get ahead of the content. I recommend finishing at least the first three chapters of maths because they are pretty easy, all of stats can be done by yourself and mechanics chapter 1,2 u can do. For biology get through the first module and for chemistry first make sure you understand everything from GCSEs and then finish the first module if you can… Chemistry is the most hardest you might find it difficult to complete by yourself so watch: BioRach, MaChemGuy and TLMaths. You are immensely regret not doing any work in the summer don’t do what I did