Wow, sounds like everything is against the consumer unless you have it written into the contract, the assumption being that the consumer has done this many times before and knows what should go into the contract to protect themselves geez!
As the HIA represents builders as mentioned, the only action the consumer can take is to take it up with the builder, who has received signed off PC and all his money, resulting in care factor being less than zero unless further expense is incurred by the consumer in seeking legal action.