how do i prove she was at fault?

I was driving yesterday along a 30 mile road. I was behind a van who was going to turn left into another road. A woman in a car was wanting to turn right out of this road where the van was turning into which would mean she would need to wait for me to either let her go or wait till it was clear. Instead of this she decided that when the white van man pulled in she would go. This meant that she crashed straight into me.
I was shocked and paniced and instead of taking a photo of the scene which you are supposed to do I moved the car out of the way so that other people could get past as did she.
I assumed she would know that she was at fault as it was very obvious.
She didn't seem to care so I said "you know it was your fault" and she went crazy hurrling abuse at me.
Her car did not have a scratch but my bumper under the front left light has come loose.
The amount of abuse she gave me made me not care whose fault it was. I tried to get in my car but she would not let me shut my door.
I then called the police but they said that it is hard to tell whose fault it is as there were no witnesses.
She is admint that I over took this van so it is my fault that she hit me which is not true.
I wonder if I can prove it is her fault?
Thank you