Thank you all for sharing your experiences.
He is home, the vet honestly doesn't know what is going on.
She has done every thing she can and is satisfied he is in no immediate danger of anything other than being stared at and falling over, off and into things.
I've hired a crate to keep him safe when I'm not around and am just hoping whatever it is resolves over time.
You're right, I'm starting to find his head tilt quite endearing, now that I know it isn't causing him any pain or problems.
He probably feels like he has the biggest hangover of all time the poor boy.