A 67-year-old man is diagnosed with Chronic Obstructive Pulmonary Disease (COPD). His FEV1 is 65% predicted, FEV1/FVC ratio is 0.65, and he experiences shortness of breath when hurrying on the level or walking a slight hill (MRC Dyspnoea Scale grade 2). He has had one exacerbation requiring oral steroids in the past year. He is a non-smoker (quit 10 years ago). According to NICE guidelines, what is the most appropriate initial inhaled therapy?