A 52-year-old man with type 2 diabetes for 10 years, currently treated with metformin 1g BD and gliclazide 80mg BD, has an HbA1c of 78 mmol/mol (9.3%). His eGFR is >60 mL/min/1.73m², and he has no history of cardiovascular disease. He is overweight (BMI 32 kg/m²). According to NICE NG28, what is an appropriate next step in his diabetes management, prioritising glycaemic control and considering weight?