Complex sentence: Wooller was a dissident member of the Institute of Chartered Accountants in England and Wales (ICAEW) who led a ginger group which opposed many of the actions of the ICAEW.
Split into simpler sentences: Wooller was a dissident member of the Institute of Chartered Accountants in England and Wales (ICAEW). Wooller's ginger group opposed many of the actions of the ICAEW.