Dragon Age II via Xbox/EA play DLC unauthorised

Yet another of these posts.

I installed Dragon Age II Ultimate Edition via the EA app, connected to my XBOX Live subscription. 

I have tried the guide on this forum, and I've deleted and reinstalled both the DLCs from the Addins folder and the game as a whole several times, but when I look at the Downloadable Content option on the DAII main menu it still says unauthorised.

I know it reccommends not doing so, but would it be better if I downloaded them from the website instead?

Any advice would be greatly appreciated?

The steps I attempted: https://forums.ea.com/discussions/dragon-age-franchise-discussion-en/pc-dragon-age-unauthorized-dlc-error-after-launch/4985922