I did my dip like a year ago. I can't remember if the examiners asked any questions about aurals at all. THe thing i know is they fired questions at me! I think they just concentrated on the grade 6 pieces and the teaching materials i brought with me. They didn't ask me any questions on music history and safety (etc) either.
I did my grade 8 in my 4th year back to secondary school... long time ago and I can't even remember the details of the aural tests now. However, I can still remember for 8A (i) where you have to sing the bass line of a melody or sth. That was where i messed up completely! lol. Im very lucky enough i sort of have perfect pitch so i can recognise the bottom notes immediately and so that i can tell different cadances etc.
I did my grade 8 in Nov time that year. Actually i didn't have a proper teacher then. He was nice but he stopped teaching me in that summer before my exam.

So what i did was to study and practise on my own. I was still learning the third piece during that time and the CD saved me! Luckily aural was not a huge problem for me so i didn't actually practise that much. I just concentrated on the three pieces and scales and worked very hard at them.
I have also had several teachers before. When they practise aural with me, they just said "try listen to the bass line very carefully.." If i have made a mistake they just play again and let me sing again and added "try listen to the bass line more carefully this time...."
From my tiny little bit of teaching experience, few of my students cannot sing a single note accurately. One of them was doing grade 5. He tried very hard on singing the note accurately but he failed. Occasionally, he could get the pitch. but then after 1 min or so he couldn't sing the pitch again.
So i would like to collect opinion and comments about how people learn aural tests.
maTThew