In Melbourne the appliances are almost never installed until the day of handover when the client pays the final instalment. This is due to theft. If they are installed prior to handover and they are stolen the builder is liable.
Also to the OP, I had another thought.
If this $27k is a variation, then variations are paid at completion not at the end of the contract.
Also if you are relying on a bank to fund progress payments then the bank should be unlikely to fund this payment.
Yes, but if a builder is smart, he will get you to sign a variation form, meaning he would then have an 'enforceable contract' of his own.
I would seek specific advise. His problem certainly should not be your problem.
pinkboy