As far as I'm aware, Apple is still signing iOS 7. Just do a google search for something like "return to iOS 7" and you'll find the directions. It involves downloading the appropriate software, and then holding Option when you click "Restore" in iTunes. Very simple to do.
Eventually, though, they will stop signing iOS 7, so it is best you do this as soon as you possibly can.
I attempted to downgrade my iPad Air to 7.1.2 and it didn't work. Not sure if I did something wrong or Apple isn't signing it any longer. I figured I would go back for as long as it takes for Apple to make iOS 8 far more complete and stable than it is currently.
I did successfully downgrade my iPhone 5s from 8.0 to 7.1.2 and upgraded my iPad 3 from 7.0.6 to 7.1.2 after iOS 8 came out. I didn't downgrade my iPad, but they were still signing iOS 7 a few days ago.
I don't know about HarryWarden's experience...just relaying my own.