Abrsm Grade 8 theory equivalent

[ruthantic]

Hi, I'm actually looking to apply to Universities in the UK to study music and psychology. I'm in Australia and I haven't done A Levels but noticed that they accept Grade 8 Practical and theory as a substitute. I don't have Abrsm Grade 8 theory and I don't know if I'll be able to find a teacher who uses the Abrsm syllabus but would Ameb music theory exams be accepted as a substitute? Ameb only has G1-7 theory. I have Abrsm Grade 5 theory but when I talked to a teacher teaching the Ameb Syllabus, I found out that Abrsm G5 is about Ameb G4. Most Australian teachers only teach theory till Ameb G6, so I was wondering if Ameb G6 is anywhere near Abrsm G8 theory and if I should do the Ameb G6 then try to tackle the Abrsm G8 on my own. Anyone familiar can help?