Okay, I read the original assignment and drew an ER Diagram based on the assignment. After drawing the ER Diagram, I counted the number of tables required and came up with 18 tables.

There are some key items that I had forgotten about and that are not included in your diagram:
1) Modules can be split up into sessions
2) Some lecture sessions can be associated with practical sessions
3) Some modules have prerequisite modules.
4) Modules are given either during the first semester, second semester or both.

Since the assignment does not mention departments or head of departments, I would leave those items out.