A small Course indeed !
GCA Courses then appear [from the photos] to be around a dozen. Of course [ooops] they may have had overlapping Courses, progressing from Basic to Advanced phases.
The JATCC [Approach and Local] then was about 24 students ... my Course was a typical mix of youth and experience, with 8 x a/plt offs! "Admiral Tim" in the centre seat, naturally!