Thought I'd update this, I've managed to get the handles on the other side. What I done was popped the plastic washer out, lined the handle up with the hole and wiggled it side to side with a lot of force. This made the opening bigger and it went through, I tightened it up and it all seems sound, nothing is catching or loose, so should be fine. Probably not the best/correct way to do it, but it worked lol