Need to find the location or registered owner of a car with only description and rego number. Neither DPI nor WA Police will assist despite the reasons being legitimate. Its 'policy'.
Been advised to write to the Commissioner of Police to get a waiver but there must be another quicker way. PI's are not interested either - 'we dont do that' seems to be the standard response.

Anybody got any other suggestions?

ring up and report it stolen

About 30 years ago you used to be able to just phone up the police dept and give them the rego number and they would look it up for free.
Unfortunately, this process was often abused by many, who just wanted the name and address of some hot chick that flew past in a red sports car, or a name and address for a bit of payback after someone had cut them off or upset their ego in some other way.
This resulted in a lot of complaints and bad publicity so it was eventually banned.
It is now supposed to be impossible for any Joe in the street to obtain owner id for any vehicle, even if the clown just backed into your your car and then drove off.
Sorry. That's the law.