Aha, thanks. It appeared the moment I installed the new iOS beta. Me and my assumptions! That would explain why it matches the theme! 
Well I guess you had people asking for it so fair enough. Was happy with swipe back though. 
PS taken a second look. I like the way it ‘gets out of the way’ when you are scrolling down and therefore focussing on the bottom of the screen, and appears at the bottom when scrolling up, when you are focussing on the top of the screen. So not so intrusive. Makes sense. Thanks!