A 68-year-old woman with type 2 diabetes is reviewed. Her current medications are Metformin 1g BD and Gliclazide 160mg BD. Her HbA1c is 78 mmol/mol (9.3%). She is reluctant to start insulin. Her BMI is 32 kg/m². Her renal function is normal. Which medication class would be most appropriate to add next, considering the high HbA1c and desire for weight management?