You shouldn’t need to upgrade the firmware to see other nodes but it is probably worthwhile doing. My nodes are on 2.5.9 at the moment but that latest 2.5.11 should be fine.
Also if you are in the CBD of Adelaide it might be worthwhile taking a walk around to see if you pick anything up. I’ve found the signal seems to be blocked by buildings in some places.
My node is 2.5.7
Only me on the map 
These are the other nodes that I see on the map. Positions aren’t necessarily accurate but give some idea of where they are. 
But I don't see myself when I checked on meshmap.org
Only me on the map 
😭
I almost gave up and threw it away now.
I’m surprised you haven’t picked up any of the other nodes. Maybe try resetting it to defaults and setting it up again if you haven’t already tried that? My only other thought is maybe a hardware issue - has the antenna connector come loose?
There is also a node at Adelaide airport and some up in the hills that are reachable from some parts of the city.
I'm unsure what's a mistake 
