Head painting exercise - 'The Champions'

This set of portraits are characters from 'The Champions', a series broadcast in the UK between 1968 - 69, and made by ITC, a company who produced quite a few similar series.
It is listed as a spy thriller/science fiction/ detective fiction series. Shown are the four main characters (upper left) Craig Stirling, (upper right) Sharron Macready, (lower left) Tremayne, (below right) Richard Barrett.