@Dale & All,
The app came for free with the GPS dongle. Not very sophisticated. Thus probably missing out on DST. I asked NMEATime2 about preferences of COM over USB vs BT. BT seems to be deprecated. More interesting the 2sec gap between Win10 clock and GPS. I had used the sync with network in the MSFT clock settings popup just 5min prior. Alas I probably hadn't let the GPS soak for long enough. Will try again.
Ping for Ray : Any ideas about hand controller / joystick override for the ISS tracking ?