In the UK the NHS provides free-of-charge health care, with a few exceptions e.g. a patient has to pay about £8 per drug on prescription.

An NHS doctor prescribes a drug that is unsuitable for a particular patient (tablet form, for a patient that cannot swallow tablets), and the doctor knows this in advance. The patent discovers this when at home, but cannot return drug (for safety reasons).

The issue is rectified by a new drug being prescribed. However the patient is expected to pay a 2nd time.

If the Sale of Goods Act 1979 applied, then the patient could return the drug as not suitable for the particular purpose.

Does the Sale of Goods Act 1979 or some other statute, apply? Or is the NHS exempt?