G'day Geoff!
I'm also in Canberra and try to observe or image (or both) most clear nights.
Tidbinbilla is a great, dark spot that's pretty close by. Canberra Astro Society also runs dark site nights and the one that I've been to was a seriously good spot, between gundaroo and gunning. Have you joined?
Don't hold back in asking questions about setting up the kit you have for your grand daughters, this is definitely the place for it