Welcome to the forum. Not a feature I use myself, but from previous posts it seems you shouldn't have an issue with WOL across the local network but might have difficulties across the Internet.
The NOW TV Hub is basically a rebadged Sky SR102 router and the NOW TV Hub 2 is a rebadged Sky Q router model ER115 so I'd recommend doing a search for WOL and those model numbers and/or posting the question on either the Sky forum or SkyUser forum as they have a much larger user base to draw upon, so you should hopefully find a solution there.
NOW are looking for users to join their Customer Feedback Group and help improve the service. If you're interested read more here and sign up.