Throughout the 12 week treatment period, patients will be required to inhale their study treatment medication (each morning) and complete a diary card. Patients will be required to return to the surgery after 2 and 6 weeks, with the final visit at 12 weeks for lung function testing, assessment of symptoms using the Oxygen Cost Diagram (OCD), Health Resources Utilisation (HRU) and any adverse events. On completion of the 12 week treatment period, a full physical examination will be repeated. Adverse event monitoring including COPD exacerbations will take place throughout the study.