Just a thought, but I simply can’t understand why Voldemort didn’t try and use a time turner from the Department of Mysteries during his attempts to regain power. If he would resort to drinking blood that literally curses him, the risks he employs when dealing with time turners could be justified, surely. Going back in time to hear the prophecy concerning him would be another one, rather than waiting. I understand that they were hidden, but still I’m sure he would have had informants within the MOM,