The piece Jo is referring to is out of '80 Graded Studies', and while the key could be kinder, I think it's a nice piece. The other choice from that book isn't terribly tuneful, in my opinion, though apart from the top A, I don't think it's that hard.
The Berkeley I think is a nice piece, why not have a look at that? The Sonata da Camera by Paul Harris is also not too 'study-like' for want of a better word.

Good luck with your grade 8 studying!