Hi There Peaches,
I applied for DLA for my daughter before I has her diagnosis confirmed. To my mind it was a foregone conclusion that she had Aspergers Syndrome. We had gotten turned down before but the second time we applied I had gathered reports from the school, GP and other associated professionals, I was armed and ready. My daughters diagnosis followed 4 months after we got the diagnosis so it is possible to claim without a diagnosis..and if you get turned down then don't get disheartened, keep fighting...I waited for 3 years to get a diagnosis for my daughter (who is 16), no one would listen but I knew there was an underlying cause and eventually I got it confirmed.