In reply to WillBroad:
Try speaking to your local team at Guide Dogs, they will be more likely to be able to give you more practical advice about the possibility than a generic email. Have you done any sighted guide training? Going on a course (these are run by Guide Dogs and others) would also give you more insight and allow you to discuss your idea about how you would like to help.
I suspect many run with friends at their local running club.
Steve