If you are 18, bear in mind there's plenty of scope for backtracking a little bit if you feel you've made the wrong decision (thread subject mentions a fatal decision) and your only option is a game design degree.
You could easily study for the same 'other degree' qualifications that everyone else does, A-levels. You may even find places which accept your A-level equivalent qualification. Is it a BTEC diploma? You mention that in the title thread, but unless I've missed it I see in the thread it doesn't mention BTEC. Plenty of people I know went from BTEC to Computer Science degree and although I know that's not what you are looking for, I point it out to suggest you may not be limited to doing just a games degree if that concerns you.
It's not a fatal decision about my career choice, It's more about what my qualifications will look like to potential employees, I've read in posts that it seems a specialized games degree may not look the best, and because my a levels are pretty much, Game Development, so i'm going to have game dev a-levels, and a game design degree. I mentioned what my BTEC was in the very first post, (Sorry if it's unclear, bad wording on my behalf then)
I love what i'm doing currently, I'm just trying to figure out if what I've done so far is a bad choice for future jobs in terms of first appearance.