There was a Butler ebook bundle a few years ago (ie within the last decade) that I think included both Unexpected Stories and Survivor, and is where I got Unexpected Stories. I subsequently sent my spare copy of Survivor to a friend in Australia.

I read all of Butler's work then available in 2016, in chronological order. If any of your readers are interested it's here:
https://wordpress.com/view/carojmullan.wordpress.com