This is very sad news. I did a few rides back in the early to mid 90's at Loftus in Sydney where John was the ride leader, mostly. I was not a local but did enjoy the 'Let's ride bikes!' chant as the kickoff term while we tried to figure out what this MTBing thing was all about, but fun it was even with 135mm stems.
The Loftus trail head is here
https://maps.app.goo.gl/cYYb8CCMTjLtxA7X7
I've also attached an Australian Mountain Bike SC Heckler road test with John from 1996.
I wish the best for John and that his time is spent well with family and friends.
View attachment 904943
View attachment 904944