John Dent

British mastering engineer, Dent worked in London mastering houses Trident Studios (1973–1978), The Sound Clinic (1978–1986), The Exchange (1987–1996) and Loud Mastering (along with Jason Mitchell), from 1996 until his death on 29 December 2017.

Mastering Engineer of the Year 2014 at the Music Producers' Guild Awards, his engineering mark can often be found in vinyl runouts simply as "JONZ" or similar variants; Add a credit: Lacquer Cut By - John Dent + ANV Jonz (ANV's should NOT be created for variations in capitalization).
If the runout etching is "JD", please consider also John Davis (4) as a possibility.