Complex sentence: The large electorate of Rangitikei extends south to Palmerston North's southern and eastern ward (Ashhurst-Fitzherbert), therefore completely surrounding the electorate of Palmerston North (the only electorate thus surrounded completely by another).
Split into simpler sentences: The large electorate of Rangitikei extends south to Palmerston North's southern and eastern ward (Ashhurst-Fitzherbert). Therefore completely surrounding the electorate of Palmerston North (the only electorate thus surrounded completely by another).