A 56-year-old man with obesity (BMI 33 kg/m²) and hypertension attends for a routine check-up. His fasting plasma glucose is 7.4 mmol/L, and a repeat fasting level 1 week later is 7.1 mmol/L. HbA1c is 7.3% (56 mmol/mol). He has no symptoms of hyperglycaemia and normal renal function. What is the most appropriate next management step in primary care?