Have you looked in the syllabus? In the original 2000 syllabus (it was revised this year) on page 122 it has a grid of the qualities and marks you would get. There are five different categories: fail (0-5), pass (6-7), a clear pass (8-9), a high pass (10-11) and distinction (12-15). It's a similar grid to the one found in "These Music Exams" for the grade examinations. There are also grids for all the other componants of the examination at all three diploma levels.
I hope that helps.