I sit corrected. I can't find the page I was looking at, but following your link it does appear that you need a degree from one of about 6 accredited institutions in order to be a practicing Chiropractor in the UK. It is regulated and has an associated Royal College. However this should not detract from the fact that the "art" of Chiropractic has its foundation in woo-woo rather than science.I have not checked the rest of your post, but this one line stands out as complete bollocks. To practice in the UK you need to be a member if the GCC which requires an approved chiropractic degree that usually takes 4 years.
https://www.gcc-uk.org/education-and-registration/becoming-a-chiropractor