This is what they do at my children's school, separate the children, or depending on how serious the "bully" will walk alongside the yard duty teacher or spend lunch time in the staff room. Physical bullying is an instant suspension though. Two years of this bullying is absolutely outrageous and I feel furious that the principal hasn't taken action. I would strongly encourage you to make a formal complaint to the Department of Education and I hope some action will be taken, all the very best.

Regards,
Dianne