<p>The BT Sport app closed on 12th October and has been replaced by discovery+. <a href="https://community.bt.com/t5/TNT-Sports-on-TV-Online-player/The-BT-Sport-app-is-closing-on-12th-October/td-p/2312034">Find out more about activating TNT Sports on the discovery+ app</a>.
I've got a similar issue where i have 3 old ID's not in use preventing me from activating Discovery+ on the ID that is in use. so i can still enjoy my sport package. Would this be something you'd be able to help with?
Thanks for posting about your BTiD. As @NeilO mentioned it might be easier to delete the profile so you can set it up again using the new account. I can help with that. Please check your inbox for my message and drop me over a reply with the details.