DLA is very difficult for people to claim. My experience and that of many others that i chat to on another health forum is that the form that they send to your G.P or specialist has a huge impact my SIL's brother lost his leg in the gulf (Soldier) and he still has to fight for his DLA and they still keep calling him for a medical each year which means he has to use a days holiday to attend the appointment. Because he doesn't see his G.P like every month or so he has to attend an external doctor.The last time he walked in sat down unclipped his prosthetic leg put it on the table and said "It has not grown back in the last twelve months so that should answer all the little questions for your report" "I'm guessing that i'm still disabled then" got up and walked out. He has been disabled for the last ten years.
I myself claim DLA however i only get the lower rate, i think that if you get the higher rate your very fortunate as the government thinks you should have no quality of life to qualifty.