Well yes that is something that can definitely happen in blender it seems, but having your anchor point not sitting dead center of your object is something that could happen in any 3d software, like max. I guess if it was me, I would duplicate one of the nulls that ARE working, move it into position and rename it... if you haven't tried that already? … (just thinking out loud).
For the AC_START nodes? Already checked that. no change. And I don't know why this should have something to do with it.
Very well done, thank you very much! BTW: I'm also very glad that you omitted the balloons. Nothing against Mascot and its airships / balloons: one is sometimes very nice. But should crowds like in Willows only distract you when driving. Apart from the fact that in a real race within a radius of 30 km no balloon may start anyway (helicopter traffic)!
I'm getting goosebumps watching that! My other half lives just down the road from Goodwood, and we have been for the last several years- you have done a sterling job on this and these subtle animations have really added to the ambience I am a bit late to the party when it comes to trying this track out, despite loving the vid on Jimmy Broadbent's channel so will be downloading it this weekend if I get time off work
