Thank you for the response. In response to the first point made, I assumed something along these lines:
(I) personally feel like I would do well in the job. 'Liability' is how I think it would look like from an employer perspective, I have already failed once, so in a way, it feels like it would be more difficult to be assessed again, given the risk to the employer? I don't know. Would they rather assess the multitudes of promising new candidates over someone who has proven to not have the skills for the job? (as the tests are designed to assess)
I suppose you are right, you never know until you go for it again, and until you go for it again, it'll keep buzzing in your head! I also did pass some tests, so I might have some options in other train operators that accept those results, and avoid repeating some components, or can sit the remaining tests privately if that's an option. Whichever train operator the key comes from, I'd guess you have more freedom to move around after Qualified.
It will be my last ever attempt, though... not sure I want to walk into the test centre in November with that sort of stress! For me, this is especially terrifying, as I don't see myself doing anything else.* Which, really begs the question as to why I decided it was a good idea to show up for assessment while sick.
*Maybe there are jobs out there with person specifications similar to this, I'll try think on the bright side for now.