Myinlawsdidthisthebastards
Sorry, my cat managed to delete part of my previous post while trying to scrounge treats.
As the P&C space has no definition in law, I'd park there. You really deserve a Blue Badge as you have problems walking and getting out of your car. You need the space. Do you get problems if you've done too much? My sister could have her leg turn under, refuse to move or go into painful spasms hours after actually walking. That kind of thing still counts because the DWP guidance on the PIP form states that it's if you have problems before, during or after an activity.
I really hope you can get a Blue Badge, I can't understand why you've been turned down. I guess it's the problem with understanding movement disorders, people don't see what happens afterwards or how much pain it's causing you to walk.