The information and comments on this page have been very useful. Since a few months ago I had a massive surge of daddy long legs in my outdoor toilet/shower/shed which I haven't seen in the 3 years I've lived here. Then I noticed a few small (what I now understand to be male) redbacks hanging around my push bikes literally. Good to know the daddy long legs are their predators but I decided to clean up all the webs and found a great big fat female behind my toilet under the cistern. I killed her then kept digging for the web when I found the bundle of empty egg sacks (about 8). I shiver to read that each one produces 250 eggs. What is the percentage of the the sibling canablism? Anyhow I don't normally kill things - I even let white tail go as they like to run away. But no, not the red back. They like to crawl up into your things (like bikes and toilets) and they are good at hiding once they do that. So I have decided to go and buy spray - I've never even owned any spray but I am worried about a plague. Even though they are not so deadly I don't like the risk (crawling into bike helmets and wet suits).
One thing I'd like to add about the males appearance is that they seem to have slightly browner legs with white pin stripes around them. So keep spider friendly but not if you have an invasion of redbacks. Stop em in their tracks I say! Cheers.