This works! Dragging everything out, then resizing the constraint group, then dragging it all back it works, kind of. It does work in that now it's not getting clipped, but now the box is big so aligning it with anything else is a pain, cos it all snaps to the groups size which is bigger than the actual thing i'm containing.
Bit of a pain, but then again aligning it was a pain to begin with because of how the curves stretch beyond the top of the actual box. Maybe it's best to just leave them in constraint groups when editing the document and then removing them from the groups just before export. There's probably a way to make the actual group the perfect size to fit the content within as well. I'll keep tinkering.
Thanks for the help!!