R Chapman Looking for help "Research"

[Ziggys dad]

hi, I have come into the posession of an expensive wristwatch (begins with ROL ends with EX),on the back it is inscribed "British Grand Prix O/T 1977 R CHAPMAN" .
Even 30+ years ago these watches weren't cheap,so does R Chapman feature in F1 nowadays or was he a prominent figure back then?
Any help would be appreciated.