I have a few questions to anybody who could help.
1. Do you need a degree in psychology? Would a criminology/crim+psych degree suffice?
2. How should I go about finding relevant work experience? Before attending university, during or after graduating?
3. Do GCSE grades or A-Level choices matter?
1. Having a degree in psychology would be a good starting point, but if you choose to do another subject there's always accredited psychology conversion courses (PgDip or MSc) that enable you to achieve Graduate membership of the BPS, which is what you need to become a chartered psychologist. Then you'd need a Masters.
2. You can find work experience in a variety of places. Call centres ran by charities are option, as is anything working with disadvantaged people. Be aware that you often have to be 21 to volunteer in a prison which can limit you.
3. An acceptable standard of English and Maths is required in pretty much any job, but generally GCSE's/A Levels won't have a huge impact if you get the undergraduate degree in psychology and then a Masters. My A Levels were all science as I've always been interested in science in general (original plan was to go into forensic chemistry) but you could do anything, as long you pass them and get into uni.