I’m so sorry that you’ve been left with symptoms for so long- the NHS waits are crazy right now 
I agree with @Chrickychricky ; keep symptoms brief but focus on the well known ones. If it’s the vascular symptoms which are affecting you most, I would mention things like head pressure, dizziness or off-balance feelings, headache, pulsatile tinnitus, visual disturbances…If you have the more ‘classic’/ well known ES symptoms like the feeling of something stuck in your throat, pain when swallowing or turning your head, you could mention this too as they’re the symptoms doctors might have heard of the most. I would write these down if you don’t usually do this, to help you focus & not forget anything.
Mr Higgins & Mr Axon at Addenbrooks have published a paper about IJV compression, that might be a good one to print out and take with you; hopefully your Neuro will take seriously research by UK specialists. Here’s a link:
Dr. Higgins & Dr. Axon : Spontaneous Intracranial Hypotension Complicated by Subdural Effusions Treated by Surgical Relief of Cranial Venous Outflow Obstruction - General / Research Papers - Living with Eagle
There are lots of other research papers about vascular ES in the research papers category, if you have time you could have a read & if any mention symptoms similar to yours maybe print off another one or two…
Who were you hoping to be referred to? It might be a good idea to have a think about that before your appt so you could ask there and then. Maybe your Neuro might know someone in Scotland who does the surgery, unfortunately I think Mr Currie who is on our list was maybe promoted & doesn’t do surgery any more. A head and neck vascular surgeon might be able to help otherwise if your doctor is reluctant to send you down to England?
Have you got a partner, relative or a friend who could come with you to support you if you get anxious? There’s also a section about advocating for yourself if you think you might be dismissed.
In the meantime anti-coagulant medications can help with vascular symptoms, you could ask about that. And if you have nerve pain symptoms the neuro could prescribe medications which help with that, like Amitriptyline or Gabapentin.
I hope that your appointment goes well, let us know how you get on 
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