Have finally after 3 months of filling in forms and gathering appropriate evidence completed the DLA form and posted it :)
DS has GDD, ADHD and Autism.
I included reports from:
Class teacher
CAHMS worker
Paedatrition
Speech and Language Therapist
Continence Nurse
Family Support Worker
Social Services
All of which say more or less the same thing so hoping it is enough evidence to be awarded without numerous appeals.
Wish me luck !!