I have BT Broadband fibre. I also have the tv and sports package, SD only. I have had this for some months now. The sports channels are viewable on my TV through my BT Tv Box without problem. I have a Mac Book Pro and wanted to watch a football game on that platform. However when I try to log in I get a message "we're unable to find an active BT Sport subscription for this account. Check help pages etc ...error code ID003" Despite my best efforts I cannot resolve this.
Have you followed the instructions here Stevie: https://www.bt.com/help/id003
This should allow you to identify the cause of the issue and resolve it yourself. If you don't have any luck with it, please send me a DM with the BT ID you're trying to use and I'll check it out.