No such thing as in private property you cannot claim from his insurance.

Worse come to worse, you can always fight in the small court. The person reverse his car & then bang you, the answer is obvious unless you are stopping your car on a yellow box or somewhere prohibited, then only that person can argue.

This Mitsubisi Grandis driver also quite muka tebal & not cooperative, because since he is inside your company area, he is probably your company's vendor, customer, delivery/collection man, different department colleague or perhaps know or related to someone from your company. For small accident like this also he wanted to argue & deny.

My colleague who involved in an accident with my another colleague last year in the company compound, terus that colleague who is at fault go & report admitted his fault then proceed for the 3rd party claim.