Complex sentence: He took with him as London partner Frederick Du Croz, and left C. Ibbotson as a colonial manager-partner in Geelong; he returned to Victoria in 1857 to establish James Blackwood as another manager-partner in Melbourne.
Split into simpler sentences: He took with him as London partner Frederick Du Croz and left C. Ibbotson as a colonial manager-partner in Geelong. He came back to Victoria in 1857 to establish James Blackwood as another manager-partner in Melbourne.