I have a little problem: I'm looking for a equivalent/explanation of my schooling aimed at a British reader. What do you call the last few years in school in the UK? Sixth Form? High School?

In Sweden the education is divided into steps of three years. First nine years are compulsory and the same for all children, but the last three are intended to prepare you for higher studies or a profession, depending on your choice. It's these last three years that are causing me trouble. The option is simply to omit it from the CV.