just to reassure you, my dcs are in a good school, but dd1 in year 4 had the year of horror.
Their nice teacher left at Christmas, then they had in a teacher who was asked to leave after 8 weeks, one reason being he never marked a single piece of work. Then another teacher for 6 weeks, who was an 'interesting character' and she just didn't turn up again after Easter.
Several children with additional needs, including behaviour and several characters who clashed badly and were fine in a calm organised classroom, but who by this time were free to kick off and cause chaos.
Then, the final straw, there was a horrible car accident outside school and one of their class was killed.
After easter, when the teacher didn't turn up, the school pulled out all the stops, head (who was brilliant classroom teacher) came in and took the class. In September they were allocated the most experienced teacher in the school, and my dd who was quietly hiding in a corner, was, by October blossoming and a different child. The class was transformed, and they became a lovely class.
Don't despair, there is plenty of room for change, don't worry about the work at this point, just concentrate on being positive and let the new teacher win them over.