What attributes will be in the academic record entity? Since you will have a credits earned attribute in the studies entity, I was thinking you could get rid of the academic records entity.

Secondly, I'm not sure what the head of office entity is for. My thought would be that the head of office would be an attribute in the department entity.

Also, instead of joining the room to the tutors entity, I would have it joined to the lectures entity because the lecture will be in a specific room.

Lastly, you need to review your relationships. There are a few that are going in the reverse direction and there are a few that need to be many-to-many relationships. If you identify the necessary many-to-many relationships, you may get to the 18 table count you need.