Guy Jones was the guy. I worked at Modern Motors from 1978-81, and he was often at the dealership. He had a very cool suped-up p/u truck that I remember had racing seats, which I thought was pretty cool. I got to drive it a few times, and it had a powerful, tight feel. Great truck, I wonder where it - and Guy - are?
I believe Lee Speights started the company around 1929, and he was still there when I worked there. His (adopted) son Paul was gradually taking over the day-to-day, and at some point became the boss. I kind of recall that Lee passed away around 1980. Not sure, it's been a few years.
Really enjoyed my time there, I worked in 'parts' but was also chasing a career in music, and soon got what I wished for. I remember several names from there, but no luck tracking anyone down so long after the fact.