Awesome Wells are the CAB going to represent you at tribunal? I think you need to look at the exceptional circumatances granting of ESA, you still don't have points for that, but I think your condition doesn't score enough points although I would have thought that the descriptors describing
communication with others are those that best fit your description, I kept a short diary in the days leading up to my Tribunal to give an accurate description of how anxiety/pain affected my life, they were very interested in how many good days to bad, how many good hours in a day. How being eligible to look for work would make your anxiety and mental health worse. If you think you can cope with the Work Related Activity Group, say that - don't make it appear that you are closed to work for ever if you are not, if you can cope with trying to take part in work related activity from the safety of WRAG say so. If as it appears your doctor is a bit pissed off with the system, say so, and say that you feel the need to go through this process has hindered any recovery and theraputic relationship between you and the person you have to rely on for healthcare.
I think if you can, don't get bogged down by the doctors dismissive attitude, it is his attitude to the ridiculous system which he is forced to work within, it isn't a personal slight to you.
I've emailed someone who has some experience in special needs education advocacy. I read somewhere that the recent high court judgment upheld the decision that the work capability assessment was double discriminatory for people with mental health problems or communication difficulties/spectrum disorders.
This is "thoughts from the top of my head" stuff, you may not agree with me, but I hope me talking about this might help you think about what you can prove and put forward to the tribunal panel. I really do know its a big ask, and your anxiety will be giving you strong signals of "you can't do this/ you can't win this", but I think you can and will.