So, like many others, I was having issues with the Grand Finale not showing on my map, despite having completing each of the final events in all 9 stadium (I believe you have to get Gold or higher in each). Well, I went back and realised one had a KTM sponsor to do on it, despite already being Gold. So I did it again coming first and completing the sponsor, and low and behold the Grand Finale has popped up.
So, theres a couple of solutions here ...
1. You have to get Gold or higher in the final event of each of the 9 stadium AND complete the KTM sponsor for each (there are still a couple of other sponsors - not KTM - on the single events of some of the stadium).
2. They updated the game recently, and me gaining a higher time or whatever has triggered the Grand Finale (even though I got Gold and already had a Gold, maybe a better time?). The icon was never there before (I'm not sure if it should have been) but when I did the sponsor, I got a message from the bearded chap who does the helium sponsors saying well done, you've unlocked the Grand Finale, then another message saying something like you will now have to complete all 9 events? The Grand Finale icon appeared with a padlock symbol over it and a message saying you must complete all 9 with a little "Stadium complete 9/9" bit on it. I was confussed, so left to get a drink and came back and the padlock was finally removed.
3. I tried uninstalling and reinstalling the day before, so this could have triggered the event as above.
What do you think?