Tier Rewards not awarded

I’ve had Forza 6 for a couple of months, but have just started playing it. I’ve been busy with the excellent Horizon series. However, not long after getting my Xbox, one of my kids loaded up FM6, then quit out immediately. I’ve since deleted the save game it created at that point.

Now I’ve actually started playing it, I’ve been awarded the Tier 2 reward (a BMW) but none of the ones up to my current Tier. I’m guessing this would be down to having previously loaded the game up?

Is there a way to now get the rest of the Tier Rewards, or has that ship sailed? I’m not far into the game, so don’t mind starting afresh.