"Is he in his right to tell the police that it is nothing to do with them and any legal action should be through a civil court?"

No.

As soon as the victim reported it to the police, it became their business.

"whilst carrying his belongings into his house he has dropped the ball, he's kciked it back to him but hit the bumper instead."

This is a reckless act. What also has to be considered is how hard has he kicked this ball to damage a car's bumper? A court would look at this as more than just an accident.

sounds a bit like a stitch up to me.

Someones trying to deflect the blame.

Make sure any response is done on headed notepaper.

No need for the police in any of this.

Suggest a drop ball, and you'll knock it back to the (car) keeper.