It's not fraud. Such charges for overseas visitors only apply for hospital treatment - prescriptions are explicitly excluded, and are subject to the statutory price that everyone pays (unless they are exempt and get their medicine for free), see: https://www.gov.uk/government/uploads/system/uploads/attachm...
Thank you for finding that - a surprisingly readable source. Para 23+24 spell it out quite clearly, as does "Powers to charge those not ‘ordinarily resident’ were introduced through the NHS (Amendment) Act 1949, but were not enacted through regulations until 1982. These charges were and remain only applicable to hospital treatment."
