I don't think it matters if your work permit is issued one year at a time, or not. It has more to do with the
class of residence that a work permit is. AFAIK you can only ever have
one year of "courtesy" driving when you are an ordinary resident. It doesn't renew like the student stuff--and, as Graham pointed out, the student thing may be a gray area anyway. I only know what I was told by one person, and UK bureaucrats often contradict one another--check some of our Immigration horror stories for the truth of that!
