Complex sentence: Wakefield was not only the senior member but also clearly the most experienced politically, however the Assembly was controlled by the Constitutional Party led by Dr Isaac Featherston and they had been heavily involved in the recent criticism of his integrity.
Split into simpler sentences: Wakefield was not only the senior member but also clearly the most experienced politically. However, the Assembly was controlled by the Constitutional Party led by Dr. Isaac Featherston and they had been heavily involved in the recent criticism of his integrity.