Can fit note affect result of Appeal? SAR? NI?

I was in Support Group (CB) until result of face to face assessment. Before that, I was on IB for a long term mental health reasons.
Now I am in Appeal process.
The CAB helped me to get a fit note to restart ESA.

1) The fit note has an end date, only mentions one of my relevant diagnoses, and says the GP will not need to assess my fitness for work again at the end of this period.

Could this note affect the outcome of the Appeal?
My health has not improved since I was placed in the Support Group, and it has deteriorated during this process.
It is chronic rather than clearly episodic, but the symptoms are all unpredictably fluctuating so I never know what I'll be able to do when.

2) The HCP insisted that the records show I have only had two of my diagnoses for about 15 years instead of 55 years of medication for one, and nearly 40 years since starting medications for the other, although I've had it much longer.

Do I need to make a SAR application for copies from my NHS medical records?
The 1st diagnosis above is not relevant to my claim, but is relevant to the flawed assessment. The HCP referred to these two diagnoses together, and said they both started at the same time.
The 2nd diagnosis is central, and the history is important for prognosis. However, I have a very detailed letter from a mental health professional which includes history, symptoms and some ways they affect how I function, and it addresses risk of JSA and WRAG to my mental health. The HCP and DMs have ignored it because it is not recent enough for them.

The GP practice say I have to bother the GP yet again about this if I want to have copies from my NHS notes for the Appeal, and it appears I would have to pay £50 to search and make copies, and someone from the practice would have to be with me all the time, which is a big imposition.

If I'd been in a better mental state when I saw the GP before, or if I'd been able to print out a list of what is needed to take to an appointment, I could have bothered the GP less. As it was, I heard about each thing in a jumbled order, and I was even told by the NHS helpline that I didn't have to do anything to get my ESA started again during the Appeal process - it would just start again automatically. It is hard to deal with the complicated process when symptoms get in the way.

3) Also, could the lack of NI credits during this process affect the Contribution Based status if I am returned to Support Group?

Thank you.

Re 1) What does it mean if the GP doesn't need to assess my fitness for work again when the end date on the fit note is reached - does it mean he considers I will be fit then, or that he doesn't expect any change and he is just giving a random date in the future?

Re 2) I went to the GP practice with a note of what I would like access to/copies of, and I asked to speak to admin staff to see if this was realistic. It took a lot of persistence to get to speak to the admin manager at all, and I didn't manage to find out if it was realistic, or what would be easiest and most straightforward. The reply was that the first thing to do is to write to my GP, who is fed up with anything to do with benefits and who is away at present. Then it is up to him. So she said I can go away and write a letter. It doesn't feel like minimal problem, it feels like a brick wall and hard work, and something that would take up a lot of their staff time to be with me while I look. If it costs £50, I wonder if I should just ask for everything (a big file).

Also, she said the records would not be available before a date she couldn't remember (in the 90s??). So if I want to show that my NHS records say a condition started 50 years ago, presumably I couldn't get that.

Re 3) Thank you. That is helpful. And NI people say the credits are continuing, they haven't been stopped during this whole appeal process.

Re 1 It means your GP is fed up with anything to do with benefits. When the fit note runs out you will probably need another because otherwise your money will stop.

Re 2 Your notes go back to birth but the electronic bersion might only go back to sometime in the nineties. You are entitled to look at both. It would probably be best to deal with the practice manager and make it clear you will lodge a formal complaint if the practice doesn't change its attitude which your posts suggest is poor.

Thank you for the clarification on medical records. It was the practice manager I spoke with, and she wasn't at all clear. I would have thought she would have the authority to deal with this without bothering the GP.

She does.
Your practice is not being helpful.
You might consider changing if it is at all possible.