Behaviour can be MUCH worse at college in the lower/younger levels than schools. Reason being that 1:1 support that some children had in school doesnt follow them to college and they are suddenly expected to manage in classroom settings with no transition. College can be a "dumping ground" for kids that cant be provided for elsewhere.
I wouldnt go for 14 - 16 in college unless I had a child who schools were refusing to accomodate. Colleges are fine from 16+ & in the higher levels, but otherwise you end up with a bunch of kids that no one else will accomodate, with no support staff. So the classroom environment can be volitile.
If no resolution is found at school and there are no other schools, I would de register. Home ed kids can still sit GCSEs.