Medical evidence

The WCA form was filled in. Returned to jobcentre. Sept 2017. With a letter from previous education centre and current counselling provider. I get a date to attend a medical. I panic and know I can't get there. I see my gp for a sick note and send it in asking for a home visit. I'm sent another medical assessment date. Also advised to get gp to issue me with a letter explaining why I need a home visit. I ask my gp surgery receptionist as she won't give me an apt to see the gp for this and I'm told I will have to pay privately for it. So I agree, I have to make my request in writing so I leave a letter with the manager. I wait and wait and hear nothing, I ask them if the report is ready I'm told they haven't done one as a mistake has been made, they ticked the wrong box.
I didn't know what this meant but was told I wouldn't have to pay anything and to pick up a report 2 days later as I told them my deadline as my assessment date was looming. I get the letter and find out that maximus sent them a form back in Oct 2017 and the gp filled it in wrong and ticked the wrong box! I've sent a letter in to maximus, one to the jobcentre but have been told it will now go to a decisionmaker.
From what I have read I don't think I can request a copy of this form under the medical report act or have i read this wrong?
I've tried to get medical reports from my physiotherapists but my gp claims they don't write them! I'm more than frustrated and disappointed with my gp surgery and looking to change. After digging around I have found that the cqc reported them as inadequate last year. Do I need to do anything before I leave that surgery?