He returned to London in 1979, following an invitation to join Tim and Jim Smith in Cardiac Arrest, replacing Peter Tagg on drums.

On returning to London, he worked for the remainder of the 1980s as crew member or live sound engineer, touring with several acts including Immaculate Fools, It's Immaterial, and Then Jerico.

He was also Cardiacs front-of-house engineer at this time, and a member of the band Grown Ups with William D. Drake, Elaine Herman, Jon Bastable (The Trudy), Dominic Luckman and Craig Fortnam.

His mastering credits in addition to the North Sea Radio Orchestra and Emmett Elvin albums, William D. Drake's second album, Briny Hooves,[8] as well as releases by Local Girls, the post-Oceansize project British Theatre, Charlie Cawood, Knifeworld, and Khyam Allami's debut Resonance/Dissonance, the latter nominated for the 2012 Songlines music award.

He compiled and mastered Believers Roast's The Exquisite Corpse Game, a collection of contiguous fragments by various artists each of whom has only heard the closing 20 seconds of the previous section.

Cardiacs Rude Bootleg was recorded from the mixing desk by Mark on a cassette deck in the effects rack at the Reading Festival.