Not too sure yet, but i’m considering a gap year. But as it says on the tin! What work experience can I get in the STEM field, with only GCSEs and A levels?
You can either work on improving the technical skills on your own, or get into an apprenticeship, but what exactly to do really depends on what career you would like to pursuit in the future. STEM is a very broad field, so is it Aerospace, Biology, Chemistry, Civil / Mechanical / Electrical / Software Engineering, Pure Math / Physics or Computer Science / Software Engineering? Each choice can benefit from different skills that you can learn or level up during the gap year and the kind of apprenticeships through which to get experience, so it's really up to you to decide.
For example, an aspiring mechanical engineer would want to work on 3D CAD skills; electrical engineer - circuit design and microcontroller programming in C or Arduino; CS or software engineer - pick a programming language (Java, C#, Python, etc.) and write some code.