Complex sentence: He has held positions of lecturer and senior lecturer in voice at universities throughout New Zealand and as such has trained singers who have gone on to perform with distinguished companies such as the Cologne Opera and The Bayreuth Chorus.
Split into simpler sentences: He has held positions of lecturer and senior lecturer in voice at universities throughout New Zealand. As such Griffiths has trained singers who have gone on to perform with distinguished companies such as the Cologne Opera and The Bayreuth Chorus.