A 48-year-old man is newly diagnosed with Type 2 Diabetes Mellitus after routine screening. His BMI is 31 kg/m$^2$ and his HbA1c is 62 mmol/mol. His renal function is normal (eGFR 95 ml/min/1.73m$^2$), and he has no history of cardiovascular disease, heart failure, or chronic kidney disease. According to NICE guideline NG28, what is the most appropriate initial pharmacological agent?