Hit and Run - Having Problems Filing Police Report for Insurance

Hi folks, Thanks for reading, a bit long story, need help with what can be done.

My car was hit an run at a parking lot of a shop when I was inside the shop. Thankfully no one was in the car, however the entire boot of the car is damaged. My car has comprehensive car insurance. Raised a claim, took the car to the repairer who quoted nearly four grand in repairs.

My car insurance asked me to file a police report through which they will get the relevant third party details. Went to the police station to file the report. The cop (let's say Cop1) plainly told us that they could not file the report as the third party was unknown.

We then reached out to the shop owner to check if there was any video footage of the incident. They found the footage of another car backing into ours and then making the run. However, the old cameras couldnt capture the rego details. We went to the police station again with this update. This time, there was another constable (Cop2) on the counter desk. He mentioned that he will follow up with the shop to get the footage details and sent an email to the shop after another few days. The shop sent the footage through to Cop2.

In meanwhile, we checked another shop on the same street to see if the same car specs were captured during similar time and to our relief they had the footage of the other car including the rego details. They were happy to share the details with the cops too.

Went to the police station the third time. Cop 3 at the counter. Took the details of the second shop and the previous 2 constables who were involved. He sent an email to the second shop for the footage with the rego, but told us that Cop1 can only take this further as we spoke to him the first.

Few days later received a call from Cop1 (who was back from absence) and asked what the updates were.

Now,
Cop1 mentioned he does not have any footage details as those were sent to Cop2.
Cop 2 is on leave or training and can't access his emails and in possession of footage with the incident happening.
Cop 3 sent an email to the store for rego details and footage, but we dont know if those were received as it involved submitting a web-form.

Not one of the cops are willing to file a report without the full details. Car insurance says, they can only retrieve the third party details from the cops. If we cant provide the police report then we will have to pay the excess.

Where do I go from here?

TL:DR
Hit and run, multiple cops have small pieces of evidences. We did the investigation on cops` behalf and still they are not filing the report required for by my car insurance company.

Thanks