I am sorry to hear about your painful situation and to know that it has gone on for so long.
I want to clarify that when you went to your GP and had the surgery, in Jan, that it was 2009. If that is so, than you will have to give yourself more time to heal and to rehabilitate. You should be followed by orthopedic surgeon and he will send you for physical therapy as soon as he thinks you are healing properly. This will take time to gain back optimal use of that ankle.. I suggest that you have a radiologist or your doctor read the original xray that was taken at the hospital (after the accident) to determine if you had a severe sprain or an actual fracture. If it was not fractured at that time, then walking on it and putting your weight on it could have lead to the fracture and the eventual pain.
In the meantime you will continue follow up with the doctor, have the original xray re-read to determine that it was not mis-read at the time, because if it was actually broken at that time then treatment should have begun immediately. Please talk to the doctor about physical therapy and rehab schedule for you.
Now I have a different picture of things. Since the surgery was done 2 plus years ago, you should be healed, if all went well. You also should have had some type of rehabilitation, including physical therapy. You've not mentioned having any rehab. If the xray was read as a sprain instead of a fracture, then you continued to walk on it etc., which could have made things worse. I suggest you speak to a legal expert about that matter and see what your options are, as far as having the costs covered, etc. Try to get a hold of the original xray. Your treatment will be based on the xray and scan results and visualization of the plate and screws. This must be reviewed by your specialist.
Let me know how I can help you further.