[2] As Motley biographer Michael Mullin noted, Percy's aims for the school "hearkened back to the London Theatre Studio ideal of a ‘company’ who work in happy collaboration, rather than a group of individuals in creative competition with each other".
[3] In 1966 a room was found for Percy to teach in, in nearby St John Street, and the Sadler's Wells Theatre Design Course began with 8 students.
In an interview with Michael Billington in 1991, Percy Harris explained her philosophy of teaching: “It's all based on the work of Michel Saint-Denis…(who) believed that the most important person in the theatre was the dramatist, then the actors, and then the director and designer.
In 1971, the school moved to Camperdown House, Aldgate to be near the company, and at this point became the English National Opera Theatre Design Course.
Teachers at this time included Bill Bryden and Maria Björnson and students were also taught by the creative team at English National Opera who worked in the same building.
As Jocelyn Herbert noted, "the school went through numerous financial crises, and many changes of venue; the fact that it survived was due to the loyalty, generosity and hard work of a small group of supporters inspired by Percy's dogged determination to keep it going.
Teachers during this period included Lindsay Posner, Mike Leigh, James Macdonald, Steve Tompkins, David Eldridge, Simon Stephens, Martin Duncan, Philip Langridge, Michael Attenborough, Steven Pimlott, Katie Mitchell.
In January 2011, the Alumni and Friends of Motley Theatre Design Course[8] formed to support the school through the next testing period in its long history.
After a robust campaign, and facing significant pressure, the chairman John Simpson gave a public speech at the opening of the annual student exhibition at the National Theatre, reversing his decision and announcing that he would find a way for the course to continue, saying that he could not "look Percy in the eye if he met her at the pearly gates".