 The 1958 Hazelcourt Flats in Claremont Grove is an example of their work from this period.Another of Treadwell's successful collaborations was the Willeston Galleries in Manners St with H. H. Geddes.He chaired a SANZ committee on drawing office standards and was actively involved revising the syllabus for architecture drafting courses for the Technicians Certification Authority of New Zealand.