I think for grade 8 the scales are 4 octaves? In this case, I'm pretty sure there's only 2 places you can start them from, of which I think the preference is the lower octave.
Thank you for your answers! Yes, that will be my first grade exam. I studied music abroad where the music education system is different. No worries, I know about 3 pieces, etc. Just wanted to double check couple of things. Regarding scales is OK to start from any octave?