So I left Esbern and Delphine behind and went ahead and solved the pillar puzzle for the bridge to get to Alduins Wall, except now that Esbern has caught up he and Delphine are stuck at the bridge and wont go over it. So this stops me completing anymore main story line quests.

I know this is a known bug, Im just wondering is there any way I can reset the quest (I dont mind playing the quest through again) so I can finish it and progress through the game?

Starting again from scratch would be devastating and may even make me give up playing the game (I just dont have the time to go through it again).