A 56-year-old man with long-standing type 2 diabetes and hypertension presents with progressive ankle swelling and frothy urine. His eGFR is 32 mL/min/1.73 m2 and urine albumin to creatinine ratio is 120 mg/mmol. Blood pressure is 150/92 mmHg on perindopril and amlodipine. According to Australian guidelines, which change in therapy is most appropriate to slow progression of kidney disease?