Like I said gill, there really is nothing that can be done, if she plays up, she plays up! the school should be able to put something in place for her behaviour wise - they deal with kids all the time who are more challenging so will know how best to deal with her.
Abi has always been a law upon herself - pmsl - she seems more of an active child than a classroom child, and most teachers know how to tap into that and get them to perform.
It might just be that she needs to take a bit of time out from homework and start afresh in spetember, we put too much pressure on these kids and they are coming towards the end of the final year and need a break!!
I know a few kids in Joshs class whos behaviour has changed and they say its due to all the changes coming up!