Like you said BT TV did offer in the past a Day Sports Membership directly through them according to this link help article.
But if you got it from the horses mouth that BT don't do the Day Sports Pass anymore and there is no option on your online BT TV My Account section.
Then the only way I can see around it would be maybe create a separate NOW account for any future Day Sports you want to purchase in the future which would be a pain in the backside and manage such has sign outs and logins on your playback devices.
Together if you had Boost with BT and wanted the Boost benifit for the NOW Day Sports Membership you would have to pay twice.
I can see you got the answer over on the BT Community Forum that BT still offer the NOW Day Sports Membership 👍.
Thanks for the reply yes it’s either do that which is a pain or pay more money for Big Sport on BT which I didn’t really want to do. Unless BT have made a mistake as it says they do it but still can’t add it on website.
Sorry to trouble you, but did you ever sort out buying Day Sports Passes direct from BT TV ?
Where another NOW forum member who is a BT TV customer is encountering the same problem on this thread here.
Any input would be appreciated.