Hi Andrew,
I don't think it's unreasonable that further investigation is needed at this stage, although you will need an MRI arthrogram to determine the full extent of your problem - it may well be a TFCC problem like you stated or else ligamentous instability - the ulnar neural exercises you are given may well help with some of your symptoms, but they won't cure what interface is causing the nerve to become tethered, and to be honest the physios treatment should not be very painful consistently. Either see a clinical specialist Physio in hands, or else see an ortho surgeon with a view to getting an MRI arthrogram. I know it's easier said than done, but you should look into different career paths based on the history you have with your wrist, and the potential existing problems you have, best of luck!