Dwp gp report requested

Hi all,
The dwp have contacted my surgery asking for a report but I've not seen my GP specifically about my long term chronic illness/pain etc as they can't help me. I've now got an appointment with a gp I've not met before 2mrw to talk about how my conditions affect me etc. Are there specific questions they ask the gp to answer? Any advice on how I can help the gp understand my issues. I like many others I'm sure feel that I'm written off as attention seeking or exaggerating yet I still can't accept my diagnosis myself and would give anything to be back to my old self