Hi Ash
I'm in the UK too.
After my accident my GP said to go the opticians and get fully tested. Most tests were fine but there was some query about one of them and I was sent for an MRI which was negative (I've not had any trouble with my eyes since so I think it was an anomaly).
My symptoms are pretty different, the only ones we have in common are the light/sound sensitivity, although I did experience some nausea at the beginning.
I can't give you much advice about the specialist appointment, but if you want any advice/support re your symptoms (any improvement since the concussion?) and navigating the NHS to get help, let me know
Headway, a brain injury charity in the UK have been really helpful and supportive for me, might be worth giving them a call