Theres a 'BBC Radiographics Workshop' CD (reissue of the original BBC LP) that's a very good place to start - it may be OOP though. Check out also Youtube for film showing demo of the radiographic working techniques and tape manipulation.
Apparently her personal tape archive of radiographic recordings (found in her attic I believe, after she died some years ago) is being restored at one of the universities (Manchester?). Some of the material from about 1970 sounded way ahead of its time - sort of prototype 'house' music, almost. What I found particularly intriguing was that one of these tracks was clearly influenced by WW2 bombing and air raid sirens - as a small child in Coventry she was witness to the blitz attack that wrecked the place. Menacing stuff !
An intriguing musical mind and gifted mathematician. Indeed, she approach music largely from a mathematical viewpoint of Fourier analysis etc.
Also recommended are the Trunk CDs by one of her BBC Radiographics colleagues, John Baker - who was much more jazz oriented.