Ours loved the Sticky Kids Cds. Once they were familiar with the songs & routines it was a great activity.
We also had a 'Time out area with someone ready to take the children who'd had enough bobbing & dancing
.. not sure if you have a staff member/TA to help out for that but it was good for the more challenging children to be able to step away without causing too much disruption for the others.
hth and huge best wishes for the assessment