At the end of the year, your school will submit two things to the Board of Studies about its students; the ranks of all the students, and the quantity of marks that seperate the ranks.
I would hand the letter to everyone you can. Then everyone knows about it. Maybe you have a teacher designated to organise timetables at your school. I wouldn't know, as I obviously don't go to your school.
As for them forbidding you from the course, I don't know what is true, people are...
How was the exam? Are you looking at 80%
When you get your result, write a letter, outlining everything you have said here and ANYTHING else you can think of that will support your case. Put some effort into the letter as well. Hand a copy of the letter to your deputy, and perhaps the head of...
The people at selective schools, or any school for that matter (I'm looking at you sonya), who are "top-performing students" that use competition as motivation need to wake up and realise that the students in their class are not the people they will be "competing" against in the HSC, it will be...