Both my girls are little 5foot 1 or 2 little dots.
Eldest didn't do grade 8 as really there were no pieces she coukd get her hands round well enough and dd2 is likely to be the same.
They aren't career musicians so it's not real problem, just an annoyance . I guess there are techniques they should be learning that their teacher hasn't noticed ( 6 foot plus with " man hands"!)
Anyone know? The little 11-12yr old chinese piano stars can do it ...