I am so sorry you've had these falls - that fall on the road & injuries would have been horrific. I hope you are recovering OK from it xx. I am so glad someone helped you.
I've been on Arimidex/Anastrozole for about 4 years now & I've not noticed a change in my balance (other than at nearly 70, definitely not able to stand on one leg anymore with my eyes shut!!) I am putting that down to 'general ageing'.
I am currently on a 5 week break tho, as my joints were beginning to ache badly again - specially my right hand, which is back in a splint .....
Have any of your 'ologists' given you a full body MRI/CT to get a full picture of your whole body? It is always good to have a 'reference point' on your body anyway - so if not, put in a request that one is done. If one of the Ologists says no - try another one. ;)
Take care & all the best xx