Hi James,
Knowing and being able to use design patterns is very useful, both in this assignment, and in every day work. However it is not essential.
To give an analogy: a child learning to talk picks up basic sentence structure and grammer long before going to school and learning the official rules. And people understand the child even though the grammer may not be perfect.
You should realize that design patterns are tools - they help describe your solution to other people, and when designing your solution they can assist you by giving you a standard solution to a problem. But they are not a solution in their own right - you will not loose marks if you do not use the "Command Pattern" in your solution (just to pick a pattern at random), but you could loose marks if you try to force usage of the Command Pattern where it doesnt belong.
Oh, and like the others who have answered, I consider
Head First Design Patterns a great book on the subject.
Regards, Andrew
[ February 01, 2006: Message edited by: Andrew Monkhouse ]