Thanks so much for your thoughts @KoolDude; I really appreciate it. My logical brain which was an asset (I used to be a software developer, a computer programmer back in my day) is really not working these days!
Unfortunately there is no protocol to treat brachiocephalic vein compression at the moment; I’m not sure it’s even a recognised problem yet. I thought Vascular Eagle was rare! Maybe this isn’t rare, maybe just under diagnosed. I can’t find anything else online except a paper on transient amnesia, several on stenosis relating to fistula treatment for diabetes and one comprehensive paper on venous reflux -
Left brachiocephalic vein (1) is compressed to occlusion between the… | Download Scientific Diagram (researchgate.net).
I had a CT venogram with shoulders shrugged too, which strangely showed little difference and I have studied it extensively. I can only think it was a slightly different position.
Dr Higgins advised that stenting the brachiocephalic has a high risk of thrombosis in his experience and that treatment for this condition is a number of years away 
I am hopeful that the op for the jugular will make some difference as this is the area all my discomfort and pressure is. Dr Higgins is fairly optimistic and certainly the ballooning of the jugular gave me noticeable but temporary relief. I also suspect that perhaps the compression of the jugular is much worse with head movement as I know tilting my head down definitely makes things worse and sometimes turning left and right even a fraction brings on the pulsatile tinnitus. I also think you were right that general inflammation of the carotid sheaf is exacerbating many of my symptoms and I think that a number of facial, neck, back muscles are involved, certainly the scalene. .
My theory is that it all stems from something structural, as I know my body is twisted and this is the one thing I can identify in my daughter, who is also showing symptoms worryingly. My atlas is rotated on the right I’ve noticed. Apparently a hereditary element is something Dr Higgins has already come across. My father had all of my symptoms, even the drooping eyelid, left leg issues, right hand tremor and he ended up bed bound. He was diagnosed with MS, as was his mother before him, but had no MRI, so it was a diagnosis of exclusion. Whether he was misdiagnosed or the conditions are related is a debate for another day. Either that or it’s a coincidence which seems unlikely.
My only hope with the brachiocephalic is to try and improve core strength and posture to try and lift the sternum off the vein. I also have an aberrant right subclavian which may make a difference but my impression from Dr Higgins was that he didn’t think so. This is the CT for interest.
Any thoughts? Yow would think if they could shave the atlas they could shave the sternum?
Sorry I have gone so much off topic. Maybe it will help someone else looking for answers.
BTW I wanted to let you know that my lumbar puncture seems to have cleared my head a little for the last few days! Hence why I’m back on this forum; don’t usually feel up to it.
Thanks again 