I love it !

All fruits look so beautiful and tasty !

Most beautiful foliage has the second Sydney hybrid.

They may not necessarily be X pollinated. They seem to look like the Sydney Hyb "virgata" and a bit like either the finger lime, or the round lime, which are the original X parents.
Not sure I can see much other "Citrus" in them ?
If virgata really is a fingerXround hybrid, nucellar seedlings will be identical to virgata.
but monoembryonic seedlings should be somewhat variable, with traits from both parents, even without any X pollination.
X pollination of monoembryonic virgata with Citrus, would intro even more variation.

In 'The Citrus Industry, Vol.1' it says that Sydney (= xVirgata) is seedless.
I remember querying this with the CVC at Riverside, and they replied that their fruits do have some seeds.
When I was in Sydney in 2000, I couldn't find the original tree in the Sydney Botanic Gardens. I subsequently contacted Prof. Mabberley, then garden director, who said it was in the Palm Grove but in poor condition. Another later visitor to the gardens then tried to locate it in the Palm Grove but without success. I suspect it no longer exists.
Mike/Citrange

That Sydney Hybrid was a populary tree in the european botanic gardens and orangeries.
Maybe there some trees still exist.