That sounds reasonable OP, assuming you're going to put the child's name in place of LAC.
I might make some changes to make it clear who was saying they couldn't concentrate and also to be specific on what response you're hoping for.
DC has come home today and told me about a situation in class that has upset him.
DC said LAC was walking around the class shouting during lesson, and then the class went out for an extra play. When the class came back, DC saw LAC was being held down on the floor by TA and LAC continued to shout. DC said he couldn't concentrate in class whilst this was going on.
Whilst I appreciate that my child has only a partial view of events, I am concerned for two reasons. Firstly that this situation may have been distressing for LAC, and secondly it has been very upsetting for my DC to witness this incident.
I am worried that situations such as this are contributing to DC's anxiety and feelings of being unsafe in school and not wanting to attend.
I understand you cannot discuss the details of other children with me but I would like some clarification on the school's policy regarding positive handling and how the safety and wellbeing of the wider class, including my DC, is being maintained during these incidents.