Hi King Timmy,
According to Tighten Up: the History of Reggae in the UK, Vista began operation in 1980 by one Jeffrey Collins, and Culture Press was one of its many subsidiaries. At least in the beginning, the material was legally sourced from Bunny Lee, as well as Jah Thomas, Jah Life, Niney, Linval Thompson, Roy Cousins, Mandingo Williams and Tad Dawkins. The authors mentions Tads specifically, saying that Vista was essentially re-releasing identical albums that already appeared on the Tads label. Also, the mysterious Reggae Masterpieces in Dub sets credited to Roots Rockers, are "actually reissues of dub LPs first released on other labels back in the mid-1970s" according to the authors.
It really is an interesting label, some cheaply re-packaged issues of familiar LPs, but also some great sets that seem to be unique to Vista. The Tubby LP King at the Control and Earl Sixteen's Shining Star come to mind as great albums I return to often.