From what I heard, he didn't bow, as is protocol. He turned his back on the Queen, he was walking in front of her and just generally being his charming self.
IMO, a gentleman would always walk half a step behind a lady; should she stumble, the gentleman is in a position to assist. In the photo of them inspecting the troops, he's at least 2 steps ahead of her.
I get that she isn't America's Queen and if you don't want to follow all the royal protocol, some of which is a bit over the top, fine. But for Pete's sake, at least act like a gentleman!