Comprises:
- 1, Computer, Elliott Bros, Reports, correspondence, 1953;
- 2, Computer, Elliott Bros, Opposition (BTM Co), correspondence, 1953-1954;
- 3, Users' Association 405, File 1, minutes, 1957;
- 4, Users' 405 Association, File 2, minutes, 1957-1959;
- 5, Users' 405 Association, File 3, minutes, 1959-1961.