Kosen Rufu according to SGI-UK

Kosen Rufu is the widespread propagation of the Lotus Sutra. It is not spreading Ikedaism, unshakable happiness, social or political activism, or even world peace. The Lotus Sutra Chapter 16 teaches, “It is not as the Three Worlds [the people of the past, present, and future] see the Three Worlds. In such a matter of this the Tathagata sees clearly and is without error.” This is the Eternal Pure Land of the Buddha where the Buddha goes about spreading the Lotus Sutra. Unshakable happiness is the Buddhism of the True Effect [Buddhism of the Harvest]. We practice the Buddhism of the True Cause, sowing the seed of Buddhahood whether we are happy or sad. Only a Buddha with a Buddha can exhaustively penetrate the reality of Namu Myoho renge kyo. 

Reading SGI-UK materials, one might conclude that kosen rufu is spreading anything and everything other than the Lotus Sutra:

The Kosen-rufu Movement -Soka Gakkai International

“Daisaku Ikeda became the third President on 3rd May 1960 when he was 32. Under his leadership the organization grew rapidly and expanded abroad. In 1975 Soka Gakkai International was established and he became its first president. There are now more than 12 million members in 188 countries and territories, and Daisaku Ikeda has conducted dialogues with scholars, cultural and political leaders around the world. He also founded the Soka University and the Soka Schools, the Min-On Concert Association, the Tokyo Fuji Art Museum and the Institute of Oriental Philosophy. The SGI continues its development as the organization of ‘human revolution,’ the individual’s inner reformation, and establishment of Buddhahood as the core life state, based on Nichiren Daishonin’s teachings.”