If you do go into the cave (not recommended) watch out for the ... BIG BAT!
On our way out in Wednesday night, we sat down for a couple of minutes at the inner side of the 2nd Choke. When we were ready, I turned around and the biggest, fattest bat I've ever seen was flying straight towards my face! Embarrassingly, I let out a little surprised squeal and the bat turned around and flew back into the choke. It came back a minute later, turned again and disappeared into the choke, not to be seen again.
I can't really tell one bat from another but I'm assuming it was a very well fed Greater Horseshoe? Big, round, brown and hairy!