How to prove it wasnt my fault..?

[EgoXR]

During this week I drove my ute up somebodys rear. Through no fault of my own. Was a little hilux ute, with an aluminum tray.

It was on Canterbury Rd just over blackburn rd, it goes from three lanes into two. I was merging from the left lane into the next, when this bloke was behind my car. the traffic in front of us was slowing down as was I.
I was indicating and was clearly halfway into the next lane, Then the same guy that was behind me darted around me in the next lane, then pulled in front of me, when clearly there was no room, and slammed on his brakes to avoid hitting the traffic infront which was now stationary. Now at the point of impact, he was half in my lane and half in the lane next to mine, hence me only having damage to my FRHS.

I dont have a witness, so its my word against his. When we pulled over he basically wrote down his details in his car, got out after a while, rudely and abruptly asked for mine, got in his car and drove off. It seemed as though he had done all this many times. it was his works car.
I was a bit gobsmacked by his reaction and didnt check the details he gave me, which excluded and insurance company and a rego. I spoke to police who gave me his rego and works phone number, they also said I was in the right.
Without a witness how can i prove that he is in the wrong?

Heres some pics i took before. The damage is in excess of 2k