Good.update:
d's best friend's mom and i insisted on a conference with the administration, us, and the other kids' parents. that is happening monday.
I did some research on the UK situation- by law schools have to have an anti-bullying policy in place. It might be worth suggesting that this might be a good idea for this school, as they obviously don't have a procedure in place for this sort of thing. It happens all the time with kids, at different levels and intensities, and they should have some plans ready for when it does!