We were awarded pre diagnosis.
I had minimal supporting documents to send and instead I wrote a LOT, from the heart and sent 30 extra A4 pages of information to each part to give a really clear idea of he needs.
I didn't do a bad day. Because unless every day is a bad day, that is a fraudulent claim. Where his needs vary I gave a detailed example of a better day, an average day and a really bad day and gave an idea of how many of each day we have per day/month.
I kept comparing his needs to his peers and explaining how they differ and I think the key part was a LOT of detail as to how those needs impact us.
You have to remember that DLA isn't awarded because they have a condition, it is awarded based of how much more help and supervision they need than a NT child the same age. Gosh I went into so much detail, even down to exactly how I have to explain things to him... At his level with a battle to get eye contact else it does go in and examples in a way of script as to how that goes. Little things like how we have to visit 4 different supermarkets to get his food because he eats only a few very specific foods that come from different bloody places. How when we go to eat out I have it ring ahead and make sure they serve something he will eat which is very specific and how it has to be delivered to the bar so I can go and check it to make sure it is perfect in his eyes else he won't eat etc.
I gave real life examples wherever I could and quantified everything I possibly could as a measure of time. I timed things with a stop watch for about a week to get an average measure and it really surprised me how much time certain things took. 30-40 minutes each time just to dress and undress.
I had heard it was really important to make up clear how this differs to an average child so I gave examples of what Amelia can do or what friends children can do and how his needs differ from them.
I added in really personal things like the impact he has on Amelia because he is violent, how I couldn't breastfeed because his needs wouldn't allow it (I hadn't even admitted this to friends at this point) and how my back is buggered from restraining him and sitting in weird places because he needs constant supervision.
It took weeks, I was going to bed at 2-3pm for 4 weeks because of this and it was emotionally exhausting spending so much time focussing on the negatives but I think all the details really helped give a very clear and very honest picture of what our lives are like.
We were awarded quickly without them seeking further information so I think it all helped. They usually contact school and GP etc but I had sent GP letters and had his key person from preschool fill out the statement part already.
I'm not sure if any of that helps, it's all very specific to us xx