When we came over here, the best we could do for ours was a state comprehensive academy. It has a 'mixed' reputation. The kids are very loud, very confident, are known locally for anti-social behaviour, and it was one hell of a culture shock for our kids. A lot of the kids felt that because they hadn't got the grades to go to the local (very) select Grammar, that they'd already been put on the scrap heap so what is the point of trying.
We acknowledged this with our girls. We also said they had a choice whether to buy into this bullshit, or whether they could be strong enough, individual enough, to keep on doing their thing, which is head down, arse up, polite and respectful as required from year dot, do your best, get the best grades you can, to make the most of the opportunities you do have.
The teachers are passionate, engaged, and they care. When they get a child that engages and cares with them. . . well, it's like a match made in heaven.
What I'm seeing in what you're doing is a lot of focus on negative consequences. This doesn't seem to be working. What about agreeing a series of potential rewards - e.g. no calls from the school for a week = X (whatever really spins his wheels?)
Is it possible for there to be a communication notebook between the teachers and you whereby each teacher briefly writes in either positive (preferably) or negative issue each lesson?
Neither you nor the school want this behaviour embedding at this early stage.