I expect there will be others like me who downloaded the trial cos they saw the game is on sale right now. I fixed it by closing the game completely and re-doing all the events I'd done. It now unlocks.
@TomFoxx @CMTGK I have the same issue. I played the demo, then unlocked. Then started career and each one says I need to complete the previous series to unlock it. Can't make progress! Was a fix ever found?