Complex sentence: In Britain Auster produced the Auster Agricola and Percival the Percival EP-9 for the New Zealand market, both robust but primitive fabric covered aircraft, while in Australia the small but more advanced Yeoman Cropmaster was developed.
Split into simpler sentences: In Britain Auster produced the Auster Agricola and Percival the Percival EP-9 for the New Zealand market. In Australia the small but more advanced Yeoman Cropmaster was developed.