how much more work would I have to do if I wanted to take Grade 8 theory after AS level?

ben again.

Depennds how much you already know and how easily you learn it.

I'm taking grade 8 next session B period. I've been doing it for 2 months. I would advice that you are strong at describing chords as all chromatic/ diatonic chords are tested. You need to be secure with figured bass and study a fair bit of counterpoint for the trio sonata. make good use of melodic material and use ideas given in the keyboard writing/ melody writing. Have a good knowledge of transposition and know what the italian/ french and german names are for the common orchestral instruments. Describe a piece of music such as in terms of phrasing, dramatic tension etc. (similar to the anthology questions if you do edexcel). grade 8 theory is roughly equivalent of the a first year theory course in university. I'm taking it as a substitute for a 1st year theory module to do a couple of modules in the second year. So don't be surprised by its difficulty! It is a lot o work unless you know a bit about this stuff already. Have you looked at grade 7 theory?

quite alot i think.

and as jason says it depends how good your harmony is. I don;t do as music, but i did do grade 8 theory and it sounds like the two are quite different.

Grade 6 theory shouldn't be too much of a problem so maybe go for grade 6 first.

It depends how much your AS tutor has taught you.
You shouldn't jump in right away with G8 though, maybe 6/7 would be a good idea first?

I'm doing grade 8 theory this term and it is A LOT harder than As level music. Also this might just be me but I find that grade 7 is harder than grade 8! wierd

grade 7 is EASIER than grade 6 definately not harder than 8