A little while ago I asked for help from the group in identifying the track/band/genre of a piece of music played as background to a scene in the TV series Waking The Dead, to which you kindly replied with your thoughts.
Since then, I've been doing some research, namely listening to the results of a search for 'psychedelic rock' on Spotify.
An early candidate for the formative piece in question was Jefferson Airplane's Won't You Try/Saturday Afternoon from their 1969 album The Woodstock Experience, in which the bass line of the 'middle eight' might have been the inspiration for the piece from the TV series. At 2m45 into the track there's a change to a slow tempo with chord structure and bass line suggestive of that from the TV series.
See what you think.