Have you got Sky Q with mini boxes? If so the Sky Q main box assumes that you have Sky broadband unless you change it. The main box and any minis broadcast a Sky wifi network but unless you have Sky broadband and a Sky router this network will not provide internet access. Your devices will try to connect to it. It will muck up any wifi networks your own router creates. Sky Q behaves badly unless you have Sky broadband - you will need to turn off their wifi using the Sky engineer settings (Settings 0,0,1 enter - google it). Unfortunately most Sky engineers don't set up Sky Q properly when they install it. Great if your broadband is Sky but hopeless if it isn't. Turn off wifi on any devices that you have wired. Hope this helps.
I have BT INTERNET using SH2 and also SKY Q with 3 mini boxes and don't have any problems with my main or mini boxes connecting to hub wifi and accessing the internet
however as the skyq uses channel 36 for connection to mini boxes you need to ensure that you change the 5ghz network in the SH2 to another channel as long as not channel 36
its a fallacy that you need sky broadband for the Sky q to work correctly
Sky Q will work all by itself irrespective of your broadband provider. The problem is that it assumes you are using Sky as your broadband provider. If your installation engineer was on the ball (s)he would have turned off the Sky broadband option at setup/installation if you are with someone else. If you are with a different provider change you Sky wifi channel to 44 and turn off both your 2.4 & 5 GHz wifi channels on your main Q box and any minis. They will still all communicate via a hidden wifi network. You can see this using Fing or probably via your proprietary routers scanning ability.