One thing I can tell you is that special effects makeup hasn’t really changed all that much since the 1960’s, except that today there aren’t as many truly gifted practitioners of hand-made special effects makeup. Max Factor (b. 1877 Lodz, d. 30 August. 1938 Los Angeles) and George Westmore (27 June 1879, Isle of Wight, England – 12 July 1931, Hollywood, California) were famous Hollywood makeup artists. Both invented many of the techniques currently used in special effects make up, with Max Factor beginning in 1908 by inventing greasepaint. By 1967 there were some truly gifted practitioners. However, today, the use of CGI (computer generated imagery) in film has actually reduced the need to create special effects by hand. As a result, we no longer have true masters of the craft. In any case, the makeup artist for Series I was Ann Ferriggi, who was active from 1957 to 1971 on BBC productions. There isn’t much about her on the internet, but I would guess she was trained for stage work and had an excellent grasp of the structure of the face and the effects of aging on the human body.