welcome to the group and there is no need to apologise for telling us how you feel. I am not surprised that you have had this bumpy ride with diagnosis because it seems that this is still a typical thing.
Hopefully your Doctors are going to have a specific and effective treatment plan for you, rather than tell you you will need regular LP's which should never be an option because of the risk of scarring in the lumbar spine. Your Neurologist should be doing more, and also he should be arranging for you to have an appointment with them for as soon as possible if he has noticed swelling. I'm not at all surprised that you're fed up I would be too, because what on earth has happened to their duty of care, and getting on top of all your symptoms.
When you ring on Monday I would mention to the secretary that you cann't go back to work until you are fit, and at the moment you are being told you aren't but would like to return as soon as you can. Make sure you insist on seeing him and make the point you are not happy with your treatment. You have patient rights and the right to enforce them especially in this case.
The position you are in now, I have been in myself and I worked for the NHS at the time, but I wasn't satisfied with my treatment or what I had been told so I insisted my Consultant see me. When he wouldn't I went to PALS which is the Patient Administration Liaison Service and told them. They then got me an appointment to see him within 24 hours, at which he did have to apologise.
I know and understand that this has made you feel very low and disheartened. You have been made to feel that way on top of being ill, and no doubt their attitude has made you feel as if you are in the way and being a nuisance. Rest assured you aren't and you have a voice, and a right to expect them to get your IIH under control.
Please don't give up hope or give in. Phone the PALS office in your hospital and speak to them if you dont get any joy on Monday. Here's the link to PALS
so you can find the one you need, and here is the link to NHS Wales
which will tell you your rights and how to complain if you ever need to.
Let us know how you get on, and wewill help you all we can. We're here to support you.