He had been in the record industry in one way or another since 1956, even as executive in A&R for CBS and MCA Records during the mid '60s and early '70s. Howells was heavily involved with record sleeve designs as well, and in the early '70s he teamed up with graphics designer John Pasche to form Gull Graphics, which produced album covers for many of the era's biggest names. With Derek Everett and Monty Babson he formed Gull Records and Songs (a subsidiary of Decca Records), which Howells ran from 1974 to 1982.
With Gull Records struggling, David was appointed Managing Director of Pete Waterman's PWL Records in 1982 while continuing to license the Gull Records recordings to subsidiaries through his Gull Entertainments company. In 1994, David left PWL to return to his own music publishing ventures again, with his company Darah Music, managing the likes of top hit producer Steve Mac, among others.