Oh, I can see who closed it from the log in the admin panel, and it is clearly a mistake. When myself or a mod make a post we have a tick box that will close the thread, that was ticked in error from Penny, who posted on it last. And I have done a similar thing a few weeks ago (though opened up the thread before anyone noticed) and so has Florge.. Easily done, and easily undone!
hahaha... i have the feeling I did something like that as well.... hahaha.. sorry guys.... this is all new to me...