A 45-year-old woman with known severe persistent asthma, maintained on high-dose inhaled corticosteroids (ICS) and a long-acting beta2-agonist (LABA), presents for her annual review. She reports 3-4 exacerbations requiring oral steroids in the past year. Her FEV1 is 65% predicted. According to NICE NG80 guidelines, what is the most appropriate next step to consider for optimising her asthma management?