I am not in WA so not an expert on Workers Comp there. Unlike NSW I believe the scheme is private so you can shop around the providers and get different prices (in NSW the scheme is Govt run and a set price/criteria so no shopping).
What is your occupation?
ALmost every business needs Public Liability and those with a professional service or advice need Professional Indemnity too.
If your industry has an association or regulatory body make an enquiry with them as to the preferred insurer/scheme. Sometime joing the industry association gets you a number of benefits including access to a scheme.
Failing that – email me and I can help