I'm not sure why they didn't do the exercise on the day, the website of the AeMC I went to said I would have to do it on the day? The doctor even mentioned it on the day and I had brought trainers etc in my bag just incase. He seemed to discourage himself from letting me go out to run around the block for however long it was. It didn't seem like it would cost me extra. I guess it depends which AeMC you went to.
I got my records a month or two before my medical. It took around 2 weeks, the GPs office were quite helpful when I explained why I needed them. It was simply a case of filling in a form and they emailed me a secure PDF of the scanned records. There was no charge.
The AeMC examiner issued me a letter for my GP requesting details of my case and tests done etc. All I had to do was sign the letter which had a declaration about releasing information. The GP had their own separate form I also had to complete to allow them to discuss my information. Getting the GP report was fairly quick, although there was a £15 charge from the GP, and the report was issued within a week as I had my medical in around 2 weeks of my medical date.
Everything was done via scanned letters and email. I didn't visit the GP office and only spoke to them once when paying the fee for the report.