All I can say is firstly I am sorry for you having an experience like this when there are so many mechanics that do take pride in their work.
secondly if this "block butcher" has screwed you you can bet he has been doing this to people in Toowoomba for some time,and there will be many who would come forward if you went about a complaint correctly,and I mean that by documenting everything that has happened without letting your emotions cloud the isssue at hand,you will win in the end.Take the offer of one of the sponsors to look at the motor even if you have to trailer it to the gold coast,pay for a written report,and then seek legal advice. Hope this helps regards Bill
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Regards Bill