I have a feeling its pretty easy to determine if its originated in the inner ear or not ... if you get Vertigo attacks, 24/7 fluctuating tinnitus (especially unilateral!), and dizziness that morphs in character day by day, without having had a migraine in between, I'm pretty sure that suggests an inner ear condition. That said, sounds like you are getting migraines for sure! But migraines need triggers, and if you look at Hain's material on his great dizziness site he notes that PLF, BPPV & Menieres can all give you migraines. Basically ear trouble can give you migraines. But I suspect not of the type you are talking about - whilst my eyes are affected its not like I go blind if I have a vestibular migraine - quite the opposite, I have to fix my gaze on a single spot or I become very uncomfortable and nauseous - I can't even close my eyes.
Some believe that migraines are also vascular, but that is very controversial.
I personally had a very clear start to my symptoms and it was due to some kind of physical trauma to the ear (I stupidly pointed a shower into my ear). Migraines started almost a year later after I'd had almost all of the other symptoms already. After about a week of prophylaxis, my migraines vanished and i've not had one since, but I did have vertigo spinning attacks from time to time afterwards, but these were infrequent and rare apart from a phase where they happened once every two or three days for a period of about 3 months.
But we are all different ...
It would be a very good start if they actually monitored a few people in a hi-res cone beam CT and perhaps a functional MRI during a Menieres or MAV vertigo attack to cast light on what a vertigo attack is ... amazing this has not been done yet because I used to get vertigo attacks almost every other morning so a short hospital stay would have elicited many appropriate opportunities for scanning for sure! Although, of course, the CT scans would expose the patient to radiation so this might not be ethical nor safe if done just for the study and not part of a treatment programme.
Doctors in the UK will be unprepared to book you for scanning if its unlikely to change your treatment programme, which kind of makes sense, but its very annoying psychologically as it might shed light on the cause of your condition, if not the solution.