Right, so before I even go into detail, yes, this contains spoilers...it's quite obvious.

Anyway, after using the Elder Scroll at the Throat of the World, I had gone back in time and everything as intended. Everything had gone normal, dragon shows up and talks to guy, random lady kills dragon, random mage shows up with Elder Scroll, and then this is where the bug comes in. Alduin is supposed to drop in and try to kill everyone or something (it bugged, I wouldn't know) but he doesn't land. Instead, I have 3 people standing there looking at a word wall with their swords drawn while the sky is red and full of dragons, and although it's a lovely looking scene, i'd prefer to have the game running like it's supposed to having them be fighting Alduin (or whatever they do, he doesn't land).

Any way to fix this?

Read the elder scroll outside of the time wound, wait for about 5 hours, read it again inside the time wound and don't touch anything until you hear Alduins voice. This works about 99% of the time.

Thanks. That got it working.

WTF bethesda, BUF on the main quest? Im starting not to like your games and your company....