Powerline adapters* are good - I've used them for years and they are very reliable but can cost a bit so I'd do one more check before spending the money.
Work out the distance a cable would need to go to connect your ISP's router to your sky box directly (as a temporary measure) then get Ethernet cable from the likes of Amazon - you can a 15m for under a tenner. Once you have the cable just link the Q box and the router and setup a wired connection. It should be up and running in a minute or so. If all is good you can then decide on your home plug options. (The cable can be kept for future use.)
Alternatively if you have access to a shorter cable - I think the Q box comes with one? - and you have the ability to relocate next to your router (you'll need a small TV as well!) you can just set up quickly to check the wired internet works. (You don't need access to satellite signals to check this,)
*(Different brands/speeds are compatible but I believe the network created defaults to the speed of the lowest rated home plug. You won't get the speed quoted but a 500 Mb plug will be more than fast enough. Some come up to 3 LAN ports which you can use for other devices - TV, games console
