I'm afraid that I don't know anything about the Prefabs, but the "Parkside experimental Centre" off Sheepsfoot Lane was experimental ( in the early 1970s when I did a short stint there, at least ) in that groups of primary children were brought in each day from different Schools for a couple of weeks at a time, and worked with staff from the centre and their own schools together, as "Teams"on fairly free-form cross-subject projects round a basic theme, culminating in a display /exhibition at the end of the time, showing all the work. I seem to recall that parents may have been invited to this. Each team was based in one or two of the rooms grouped round courtyards. I seem to remember some flowerbeds, and a lot of use made of the Hall and Gardens. I think the Head then may have been called Miss Langden or Longden? I had the impression that the Schools invoved were deliberately socially diverse