Yo Seamus!
So that machine is all original?? Wild. Looks like it has a dirt tube muffler, like the US Conquest upright. Those machines arent too loud and with that muffler it would be even quieter.
About that outer bag: I ordered a NOS Hoover bag made of that same material not too long ago. When i opened it, i noticed it had a very odd odor. When i slid the top off for the first time it tore very easily. The bag had dry rot allover. The threads would turn to dust when rubbed between my fingers. I hope your bag is much stronger!
Its amazing that this machine was produced until the end of the 80s!