Hi Ian,
I still haven't heard back from the couple of people I emailed via Ancestry so will pass on what I've found so you can try and chase it up. This MAY not be your uncle as Jones is such a popular name :)
I found a grave for a John Jones buried Mackay who fits your uncle born circa 1888 died 21 Feb 1967.
https://picasaweb.google.com/110094840912923540046/ChurchOfE...If that link doesn't work you can go to the home page and look under Church of England Section A-L here -
http://www.mackayhistory.org/research/cemeteries/mackay_ceme...This John married Mary Theresa Ironside b. 9 May 1897 d. 10 August 1943 and married a John Jones 1917. Her father, George, was born in Eton and was a farmer. If you enter those dates into a search look at the family Wollaston-Noonan family tree. They have his DOB as 26 Aug 1887 - no place. And they have a photo of him where you may see family similarties? No parents are noted for him in any tree unfortunately. Perhaps you'd like to email them and tell them what you know? There are also some private trees you may be able to contact.
If they don't know then you may be able find out if he's yours is buying a marriage cert. Or looking in historical papers for details of his marriage.
I also had a quick look at trove.nla.gov.au which has old online newspapers - no luck but you may be able to find something.
Let me know how it goes.
Cheers
Marilyn