Complex sentence: Still in contact, the Australians began to pull back, fighting a number of well disciplined rearguard actions as the companies leapfrogged each other, while the New Zealand artillery kept the Chinese at bay after it finally commenced firing.
Split into simpler sentences: Still in contact, the Australians began to pull back, fighting a number of well disciplined, rearguard actions as the companies leapfrogged each other. Meanwhile the New Zealand artillery kept the Chinese at bay, after it finally commenced firing.