Ohhhh, dumb of me not to remember - I was only there last May

- but yes there is a massive cave beside the walking track on the way up to The Castle.
I don't know if this is the same one Aegist, but as you ascend it is on the left side (or west face) of The Castle's
lower cliff line. It's only metres away from a small creek coming off the mountain.
The cave has a small 'doorway' but opens up into quite a big cavern beyond. When I went in I was kinda surprised it wasn't wet inside because it seemed to back right up against that nearby stream. Mostly loose dirt floor.
The track's a bit rough and snaky around there, I guess it could be possible to bypass the cave on another route. Anyway, I've uploaded the only picture I have of it:
http://www.tdmskp.com.au/guide/index.php?title=Image:Castle_cave.jpgWhen we went past, a party had already 'claimed' the cave with their packs. There's a stone fireplace outside so I'm guessing it's fairly popular.
Timmy