So last night and this morning I have spent several hours trying to track down if I have the rights to a story published in 1995. I'm pretty sure I have, but as I now have an offer for further publication I need to be sure. (Generally with a short story you offer first British serial rights, so that after initial publication rights revert to the author.)
The magazine I was published in now no longer publishes fiction, but I believe has only ever asked for first British serial rights. I've finally tracked down the current editor and emailed him.
And if you're wondering why I resubmitted a story without being sure about ownership - the confession gets worse. I came across the story, liked it, thought it needed a bit of editing and had entirely forgotten it had ever been published.