The problem you have here is twofold.
The onus is on the reversing party to ensure the path is clear. Whilst I appreciate the circumstances here with the child, and give nthe age/height of the child, the insurance company are going to be obliged to deal with any claim that comes in.
Don't deal with these cases specifically myself, but as the ''injured'' party (I use abbreviated comma's here ironicallly) is a minor, the insurance company is most likely to pay out very quickly for this.
I suspect the parents are most likely after the cash rather than the child's wellbeing here.
If it ended up in court, the judge would rule i nthe child's favour every time as well.
In regards to injury payout - it's dependent no what is claimed for (note I don't say for what the injury was), as I have no doubt you'll have a claim for anxiety, bedwetting, nightmares, etc, and there is no way you get evidence to go against it.
Insurers would try to settle early with a low offer (�1000 to 2000), but dependent on what the claim is for, it could be absolutely any amount.
Makes me sick