It depends what you mean by “a positive outcome.” For some people that might mean an apology because they feel they were spoken to insensitively (if, as you claim, you were told to let the hospital know if you had a termination because they could offer your appointment to somebody else) and a commitment to include training on person-centred working for all staff including administrators. For others, it might mean loadsa dosh. When making a complaint it always helps to first be clear with yourself about what exactly you’re complaining about, what a good outcome would be, how that outcome could be demonstrated – and to be realistic about what’s likely.
If you’re claiming negligence or incorrect treatment then essentially you would need to demonstrate that the treatments you’ve “researched” (do you mean you’ve read some things on the internet or that you’ve undertaken a review of peer-reviewed medical studies? There’s a significant difference) are standard procedures available on the NHS, that it would have been appropriate in your particular medical situation for you to have been offered them, and that had you been treated by another doctor they would have offered you those treatments so that the doctors who did treat you were remiss in their actions.
Don’t muddy the complaint with things like being overdosed on GA unless you have the medical evidence of this – as others have said, being overdosed on GA would result in severe illness or death – did either of these things happen? How do you know you were overdosed? If you can’t explain and prove, you won’t get the response you’re hoping for, and you won’t feel as though you’ve received a positive outcome.
Have you sought a debrief of your treatment through PALS? Understanding why the decisions which were made, were made, is often the first step to resolution.