A 70-year-old ex-smoker with known COPD (FEV₁ 45% predicted) presents with increased cough, sputum purulence and dyspnoea for 3 days. He is afebrile, SpO₂ 93% on room air, RR 22 breaths/min, no signs of consolidation. According to Australian COPD management, what is the most appropriate initial management in primary care?