However, I noticed that using this default screen blanking the touch which unblanks the screen also gets sent to whatever program is below it, so if you happen to touch a button on the 'blank' screen, the button gets a press event.
So, in order to fix this I installed the xscreensaver
sudo apt-get install xscreensaverand then configure it using
xscreensaver-demowhich allows me to set it to a black screen, and I also noticed there is the option there to have it activate the power management of the screen to turn it off. For this application I want the screen to go off after 1 minute, so I set that, and very easily I have the functionality I need.
The screen goes off after 1 minute, and any touch instantly brings the screen on, but doesn't get passed through to the underlying application. Perfect.
I also removed the default screen blanking, as I suspect there is a bit of an issue sometimes
[SeatDefaults] xserver-command=X -s 0 -dpms