Ability to add Head of Departments to gradebooks

The same function we had before in Markbooks. We used to add HoD by just ticking the Allow HoD tick box.
Now, we can add them but we need to look for them in the staff list.
A HoD and/or HoY tick box would be so useful.
Also for only HoD and/or HoY to be able to enter marks into to the gradebooks and hide the specific gradebooks from teachers.