Casio G-Shock GW7900-1 - Richard Madden - Citadel
The watch can be spotted on his wrist in the breakfast scene at his house with his kid. It's not yet known if the watch also appears in other scenes.
The image we have is quite blurry so it's not 100% confirmed but all the details we see do match the Casio G-Shock GW7900-1.
If you have a better image of the watch in the series, please send it here.