Just purchased a few galvanised U bolts/washers/nuts for mounting a tool box direct from All Trailer Spares in Brisbane.  http://www.alltrailerspares.com.au/  Ordered them at 4.30pm AEST

Not only were they cheaper than the big green shed they were delivered 8.30am AEST following day express post to Sydney. I now know where to get all my bits and bobs.