From the MUTV website:
"[Q] Does my MUTV Digital subscription give me access to the MUTV television channel via a television service provider?
[A] No. You are subscribing to the MUTV online service and it does not include access to the MUTV television channel via a television service provider"
https://mutv.manutd.com/help
For information about the streaming devices that you can connect to your TV, in order to subscribe to MUTV, see here:
https://www.manutd.com/en/mutv-international
As I read the information on the BT TV website, the only way you can get Sky Sports News is to pay for their full (and expensive) Big Sport package:
https://www.bt.com/sport/tv