A 65-year-old man with a history of type 2 diabetes for 10 years presents for his annual review. His current HbA1c is 68 mmol/mol (8.4%). He is on metformin 1g BD and gliclazide 80mg BD. His BMI is 31 kg/m² and eGFR is >60 mL/min/1.73m². He is keen to improve his glycaemic control and potentially lose some weight. According to NICE NG28, which of the following medications would be most appropriate to add next?