I agree that most of it is staged. For instance:
1. When they bashed the caravan on the post, they would have driven the car a *** paper's width from the post to get the line right and cause the collision.
2. When they turned the caravan in the road, it then "fell off" the towball with the jockey raised. If it was merely sitting on the towball, then it would have stayed on for a bit. Unless the handbrake was deliberately left on ...
3. There were cameras ready to film the arrival of the fire engine.
I could go on ... but that's just from memory. It was good entertainment.