Thanks for the kind words of advice.
Macca, I've been seen by Occupational Health for a phased return to work and they have ruled out any lecturing for the rest of this academic year. Which is nice. I will look into recording lectures - it's been something one or two colleagues have tried in the past.
Winb143, they are ordering me a cushion and a new chair!
The consultant has written to me to tell me there doesn't appear to be anything abnormal in the full spine MRI.
I've decided to treat the giddy/dizzy spells as if I were a bit tipsy, without the chore of actually having to imbibe any alcohol! I try not to be too concerned or stressed by them. Some days it seems they last all day. I can go for days without any.