Several days ago I ordered a custom made muffler from the USA. It will be very close to the photo above, though the in/out pipes will be in different locations. While not a cheap item, it is about as close to an original as I will ever see. Cost is under $180, including the $50USD for shipping. I won't see it for quite some time. Manufacturer asks for 10-15 business days for production, and I would expect another >2/52 for the journey to AU. In the meantime, hopefully I can acquire a suitable piece of 1 & 5/8 pipe and the one remaining pipe hanger I will need to complete the job.
Thanks to Jacques earlier postings showing correct pipe hangers, I have been fortunate enough to locate the hanger that bolts tothe chassis rail. Now need to search for the hanger that attaches to fuel tank strap.