You should consider becoming a 16-19 member of the Institute of Physics. It's free.
Follow this link:
http://www.iop.org/education/student/youth_membership/page_41684.html
I've explained about the Headstart programme of university taster courses that one of last year's students went on. They are mainly Engineering and the Physical Sciences, but might help you to decide about a more vocationally based course for a subject that you haven't studied in school.
These courses cost, as far as I can see.
http://www.etrust.org.uk/headstart.cfm
