I have a real issue with foreigners doing A levels in their native languages and, unsurprisingly, getting an A* in them which they can then use for entry to British universities. And the approach you describe, 'not going to any lectures and just turning up for the exam' just makes it worse for me. It seems that you're almost getting a free hit at an A*, where others have to toil at it.
I know that to gain entry, you've got to have a certain level of English, and you could thus claim that you've been disadvantaged that way, so it all evens out. But somehow, to me, it just seems a bit unfair. Please note, I'm not attacking you personally - it's the system I'm not sure about.