A 16-year-old girl presents with a 2-day history of fever, severe sore throat, and difficulty swallowing. On examination, she has enlarged tonsils with exudate, and tender cervical lymphadenopathy. A rapid antigen detection test for Group A Streptococcus is positive. She has a history of a rash with amoxicillin. What is the most appropriate antibiotic choice according to NICE guidelines for acute sore throat?