The NHS is a gigantic organisation. Mistakes will occasionally happen.
Look at it this way - Sue Marsh has had the benefit of literally hundreds of thousands of pounds of treatment, free of charge, from the NHS, over many years. It now looks like she's aiming to take the NHS, ie the taxpayer, to court to claim compensation. That is money that is desperately needed to treat other people.
I have seen some people who are her followers, claiming that she has been deliberately nearly given the wrong painkiller because she is a disability rights campaigner. Does anyone here seriously believe that a doctor would do this? It is a wicked suggestion.
I would be very careful about believing anything she says.