You can check for yourself if BT Sport should be available. Go to the BT Wholesale page here https://www.btwholesale.com/includes/adsl/main.html and enter your phone number. It needs to say "Available" against Copper Multicast, and your line speed needs to be about 6M or faster. BT are supposed to check these things before letting you order.
They seem to have neglected to mention how the YouView box needs to be connected on the current web site. It used to be reasonably clear - and they used to send out the powerline adaptors free to all TV customers. Unfortunately, WiFi isn't very reliable for streaming live TV, and it really can't handle the multicast system that BT uses for their live channels.
I'll be able to take a look at this for you. Please send me in your details using the "Contact The Mods" link found in my profile.