The situation is interesting especially to teachers dealing with behavioural issues.(SEN).I feel their is no obvious alternative as different policies apply in different countries and intervation methods. You could share it out with the SEN Department for some ideas.Having similar challenges,my approaches were a) Rewards , Punishment like isolation room, witdraw of previlages ,consquence chart ,school rules ,school breaks to re enforce positive behaviour. b) Parent school relationship.This narrows the gap of incidences as each other provides fast information of how the situation was before the next stage . c)Other professional like pysio therapist,Psychatric doctors to be brought on board especially on the I.E.P and design of a routine structured environment.With all that i have seen great improvement and less friction.A m not sure if it works for you.