Um LightGrenades, are you sure you wrote down the correct figures for your individual section scores, because those average out at 54, not 51...
SASOL, in terms of graduate entry, the advice given by the admissions office is to do a degree that you find interesting and useful. What would you do after your degree if you didn't get into medicine? What if you decided during your degree that you no longer wanted to do medicine?
Furthermore, if you find the degree interesting, you're more likely to do well at it. In terms of easy papers to take, that's an individual thing.
Personally if I was going for graduate entry, I'd do chemistry, with a touch of statistics and calculus - but that's not to say that you'd find that the easiest, or interesting, or useful.