I picked up the 3-season DVD boxed set and watched all of The Sandbaggers a while back, to find that it holds up brilliantly. If only all vintage TV could so well match our memories of it... the episodes are mastered from decently preserved tape, not telerecordings, and while the production values are standard for 70s studio-based drama, it's the writing and performances that give it real enduring quality.
first agent was the Transworld editor responsible for dealing with writer/creator Ian
Mackintosh over the series' novelisations, and he'd told her that he
himself was a former Sandbagger. In a business filled with bullshitters, this seemed to chime with stories I was hearing of scripts being sent for vetting by some shady government department
before production. Personally I'm inclined not to disbelieve it;
Mackintosh's depiction of a credible bureaucracy, and the way in which
he invests it with urgent dramatic life, hardly seems like a fantasist's
first choice of material.
Long before the DVDs were available, I was in contact with a researcher from Kudos who was trying to track down VHS copies of Sandbaggers episodes. They served as part of the groundwork for the show that would become Spooks (MI5 in the US).
Still available from Network DVD.