After a relocation from Stockwell the school's name was changed to County Secondary School, Streatham, located in Welham Road, London. It was later renamed Rosa Bassett School in her memory and honour.
Rosa Basstt was instrumental in the first application of the Dalton Plan of teaching within an English secondary school. She contributed a chapter to Helen Parkhurst's book on the Plan, as well as writing the introduction to a book of Dalton Plan class assignments prepared by the staff within her school.
On 27 May 1920 an article on the Dalton Plan by Belle Rennie was published in the Times Educational Supplement, introducing the ideas of Helen Parkhurst to a British audience.
Parkhurst's view that education should move away from traditional, to rigid, class-based teaching and allow for teaching to be adjusted to the pace of each individual child clearly aligned with those of Bassett, as within a month Bassett had started a small-scale trial using the Plan at the school with a group of pupils who had already completed their university entrance examinations.
The results were deemed a success, and the full-scale use of the Plan within the County Secondary School, Streatham was phased-in over the 1920–1921 academic year.
Rosa Bassett's support of the Dalton Plan was considerable, and she wrote about the school's introduction of the Plan for The Times, which was reprinted as a chapter within Parkhurst's book. Bassett supported Parkhust's visit to England in 1921 by opening the school to visitors who wished to see the Plan in practice.
A two-volume set of Dalton Plan assignments covering English, Geography, History, Mathematics and Science, prepared by the staff of the school with an introduction by Bassett, was published in 1922.
In 1921 Bassett was given leave of absence from the school so that she could visit America to see the operation of the Dalton Plan there.
She also lectured in New York on the experience learned while introducing the Plan in England, donating her fees to the Dalton Association to support further visits of teachers to America.
In 1922, Miss Parkhurst published 'Education on the Dalton Plan' to which Miss Bassett contributed a chapter "A Year's Experiment in an English Secondary School."