Once the tablet setting was changed then it all worked brilliantly, with some small issues with screen resolution (3840x2160 laptop screen vs 1920x1080 external monitors). Before the tablet setting was changed then using the laptop touchscreen effected the external monitor setup as the primary screen.
I also, in Win8.1, set the touch and tablet settings so that the touchscreen was identified as the laptop screen. I use the external monitors for my main work, so have the primary display on one of these, and not the laptop screen. I have a laptop that has a touchscreen, and uses HDMI for an external monitor, plus a mini displayport for another external monitor (neither external monitor is a touchscreen).
