A 68-year-old man with known chronic kidney disease (eGFR 25 mL/min/1.73m²) is found to have a haemoglobin of 92 g/L. Iron studies show: serum iron 8 µmol/L (normal 10-30), TIBC 45 µmol/L (normal 45-70), transferrin saturation 18% (normal 20-50%), and serum ferritin 80 µg/L (normal 30-300). He is not actively bleeding. What is the most appropriate initial management for his anaemia?