I am stuck i'm in the glade and I have read the scroll but for the life of me I can't figure how to open the gate so i can get out can some please help as this is driving me nuts!!!

Firstly, this should be in the Spoilers section.

Secondly, explain what you've done so far in that part of the quest, inside of a spoiler tag, so the forum peeps can help you figure out what happened.

This is a bug that can sometimes happen, I believe.
Try reloading a save from before you entered the glade.

Yes, I reported this bug in the bug's forum.

Let me guess, you didn't have Serana follow you inside the cave, right? If not, the gate will close and you can't get out. There's no chain to open it. The only thing you can do is go back to an earlier save and have Serana follow you BEFORE you enter the cave. I fixed it this way.

Thanks will try and get her into the cave first