yumzone
The problem could be the child's age, if they do not have physical problems with walking and it is just problems related to their Autism and there behaviour outside,, then they would only be eligible for the lower rate and it would be unusual for this to be awarded under the age of five.
Have a look at our DLA Claim guide for children on the following link for more information.
www.benefitsandwork.co.uk/help-for-claimants/dla/#dlaclaims Gordon
Gordon