2 names which stand out for me, apart from the obvious ones:
Cyril Banks of Merthyr. He had the smoothest pedalling action I've ever seen (on the road or on TV) , in or out of the saddle. I remember him telling me of his first 300,000 mile club meet-up, and his amazement at the accents to be heard, from two members in particular (yes, it was the obvious 2).
John Reaney. He had spent over 4 decades underground in the coal mines of South Yorkshire. He was one of the starters in the first LEL, but DNFd. When I finally arrived back in street outside the HQ, someone offered to take care of my bike while I went inside for card formalities and food. Only later did it occur to me that I didn't know him from Adam and my bike might be gone forever, not that I cared by that point. As it happened it was John and my bike was safe. There was also the time on the Great Eastern 1000 which involved a small group of us chasing him down the not-quite deserted A1 at 1 am. We were on the hard shoulder but he had somehow got in the "fast" lane. I still shudder to recall it.