Hey Jim Rockys on the money a trailer manufacturers the go or even try a wreckers maybe a bit cheaper ring around a bit if in melb should be no problem cheers
Further to looking for u bolts. If there is a Road Teck Marine store near you or in your travels check it out was in the one at Hervey Bay today plenty of gal u bolts , boat spares ,caravan and camping supplies. At competative effectively prices.