As a keyboardist, Colbeck played with Greep, The New Seekers, Charlie, John Miles, Yes offshoot Anderson Bruford Wakeman Howe, and ex-Genesis guitarist Steve Hackett, amongst others.
He also worked as a session player on numerous recordings, including with Charlie, Yes co-founder Jon Anderson, Steve Hackett, and Vitamin Z, whose debut album was produced by Alan Parsons.
Colbeck was principal arranger, keyboardist and co-producer along with Armand Ruby on the pre-release soundtrack for "Equinox the Musical",[4] and served in similar roles for other releases from Karmic Neighborhood, including "I Don’t Want to Walk Away".
Hired initially as a session player for the recording of the group's No Second Chance album at Trident Studios, London, he was subsequently asked to join the band as a full-time member.
Colbeck was called upon to replace the Charlie keyboard player Martin Smith and began almost five years of constant touring and music making.
He wrote, "Finally, the touring band line-up of Terry Thomas, John Anderson, Eugene Organ, Steve Gadd, and myself ceased operations once Arista refused to release Here Comes Trouble, and our caring, sharing management company immediately cut off all our money in 1980.
[citation needed] In 1989, Colbeck joined Yes alumni group Anderson Bruford Wakeman Howe as second keyboard player and live musical director, and played every date during 1989-1990 tours.
Earlier in 1989, Colbeck began what would become a long-term association with Steve Hackett, appearing on a live-recorded TV show that would become the album and DVD Time Lapse.
In 1991, Colbeck released a solo album Back to Bach, [EG/Virgin] collaborating with concert pianist Jonathan Cohen, plus Steve Hackett, Milton McDonald, John Keeble, Mary Hopkin, and the Irish poet Brian Keenan.
He subsequently published several keyboard buyers guides, a Frank Zappa biography, music related and even assisted his then brother-in-law Raymond Blanc, with a cookbook.