Bushwalk Australia

This site has a great collection of trail notes for SE Qld however I can't make sense of the authors 6 digit grid ref.
Any thoughts anyone?

The notes on southee.com come from an out of print book "Bushpeople's Guide to Bushwalking in Southeast Queensland". Attached is a scan of the pages from that book that describe the use of grid references in the book.

Due to the age of the book, maps they refer to most likely follow the AGD84 or AGD66 standard rather than the current GDA94 standard. You can find an index to the QLD topo map sheets here, and a software tool for converting coordinates to GPS locations here.

There ya go shardie.
Nice one Marwood.