Can anyone tell me what decades/years these albums came out? I'm feeling they were produced in the early 1980's.

Here are some facts that make these releases from the decade 1980's .
Replacing London 01 - In May 1990, the London 01 area code was replaced with 071 and 081 to free up the 01 code range. This doubled the available numbers from 8 million to 16 million.

Update 2019
Well this is just a theory but if you listen to Shock ‎– R.E.R.B. (Produced in 1980) https://www.discogs.com/angel-face-r-e-r-b/release listen for the twinkly synth that keeps appearing and then listen to one of the tracks off of the LP Water by Bobby Heath, Eric Peters & Robert Hunter and you will hear the exact same sound.
So this leads me to believe that this is from the early 1980s. Either from 1980 when that particular synth was made that Shock used or very shortly thereafter.
Kind of makes sense to my little brain. Tell me if you agree or not as I'm all ears ;)

Is the label actually called spectrum recording studios.... or Spectrum Mood Library as I think this just refers to the series of records in the catalogue (library) ?