if you were already half way into your manouvre before she moved her vehicle, its her fault for not checking her mirrors and her surroundings, to make sure it was safe from objects, vehicles and pedestrians before she proceded to move her vehicle in a safe manner. End of!! Any competant and safe driver would not begin to reverse their vehicle without checking all around to ensure it is safe to do so. So if what your saying is, that if her car was stationary, i.e. parked up, before you started your 3 point turn. and only after you were doing your 3 point turn she dicided to reverse, then its her fault. I am a hgv-1 driver with nearly 25 years experience, and have been driving for 31 years. So i hope my experience counts in validating my answer and i hope this answer helps you. It would also be good if you could have obtained a witness to verify your statement of account of the incident. good luck, Mike