Big Mike says it right there.
All you really have to do is work harder than me, work harder than Big Mike, and work harder than anyone else on this forum....(or be rich enough to buy a heap of experience.)
Your (potential) employer will likely be increasing financial risk in the increase in excess or total insurance costs, and risking the good record of the business. You can't expect them to do this for just anyone.
The fact that you have a commerical licence as issued by CASA should mean that you are judged to be capable of flying for hire or reward, so it seems incredibly unfair that you can't get a job due to insurance requirements. When you do get your job after a while you'll realise that the insurance companies aren't necessarily that draconian in their approach and even though you have the licence you still understand the squareroot of FA about the job.
Your school/instructor will matter to a certain extent as people do source references and they'll just pick up the phone to your school. You don't want references from someone who is not respected by the community. (goes slightly against what I said in previous post
)
But to cut the waffle, just work hard.