In the meantime - I contacted supplier#2 and purchased a new "open box" Philips Remstar system one auto - the same model I have been hiring - and a second cheapie for a backup / spare / to take camping etc.
The spare unit is a Philips Remstar M series, "gently used" ex trials machine, which looks brand new.
I had a look at its clinicians settings - and found it only has 40 hours on the clock.
At the same time, I contacted supplier#10, for 2 x masks, spare hoses, filters, 12 volt adaptor and assorted bits and pieces.
so....I x brand new auto machine, 1 x might as well be new cpap, 2 masks, enough spares and filters to last a couple of years - for less than 1/2 the price of buying a bare machine here.
Top service from both suppliers - and one very happy Aussie.