Hi Andy,
I don't think so : the HDMI monitor is going to sleep just before the logon screen, and don't display a dark image. If I wake up the screen, no signal are founded by the monitor.
Additionally, the HDMI monitor is not shown in graphics properties, nor in device manager. After disabling and enabling the graphic adapter, the HDMI monitor is well detected and windows use it at the main display, with the VGA monitor configured as second monitor (this is the settings I set before reboot).
Regards,