Complex sentence: From 1967 she exhibited at The New Art Centre who supported championed her work for many years and with whom she held twelve solo shows between 1967 and her death in 1989.
Split into simpler sentences: From 1967 she exhibited at The New Art Centre with whom she had a long relationship, supporting closely her for many years. She has twelve solo shows with them between 1967 and her death in 1989.