Again, it depends on each institution but yes there is an honours system.
Highest is a I, then II.1, then II.2, then III and so on. A first honours is the top mark and hard to achieve (although harder in some institutions than others). For the scholarship mentioned above, a student would have had to get I's in all exams plus do very well on the special scholarship exam. Other medical societies like Bio Soc (biological society) may offer scholarships as well. Some offer research scholarships but these kinds of scholarships are really more for prestige, not any significant monetary value.