After leaving I.B.C. in 1973, Denis worked for various companies including Phonodisc Ltd., RCA Studios, London, The Master Room (1976-77), Nimbus Records (1977-78), Tape One (1978-89) and Porky's Mastering.
In 1996 Denis started his own Country Masters facility at his Surrey home. In 2002 he moved to the Isle of Skye and changed his company name to Skye Mastering.
In May 2014 Denis announced his retirement from mastering.