I retrieved the bird from Harpers Hold, which is then slain by the Harpers assasin.

Then, Xzar shows up and says the bird was a 'clone' of his - and he wants me to again go into the Harpers hold to rescue Montaron.

However, Rylock is now gone, and the Harpers door is locked and unpickable (gives the 'mechanism is blocked from simple spells' when you try and pick).

How do I get back into the Hold to complete the quest?

Thanks

You will be able to get back into the Hold, but you've done all that you can right now. Better go rest up.

I have played through the game before, and dont think I ever finished this quest.

I am now completed with the Trademeet, Windspear Hills, Planar sphere, Circus tent, and about to go romp on Bodhi in the graveyard.

I still cannot get into the harper hold.

How long do you need to wait?

Thanks

SPOILER
-
-
-
-
-
-
-
-
-
-
The only other way is to do something for the harpers or if you have jahera in your party. Sometime during the chapter with the druids grove and Windspear you will rest and when you awake you will get mobbed by some thiefs who will slit her throat with in correct dialogue but either way you must fight them, afer that a harper comes up and says that she needs jahera to go to the harper building and she goes and will leave he party but does come back. After that im not exactly sure what hapens but i do know that you go back in there and fight a party of harpers(tuff battle, Cone of Cold works well). Then you will be able to go upstairs and complete the task.

<font color="lightblue">Leave a party member in the doorway when you talk to Xzar. </font>

Xzar's "Clone" is a part of TDD, as a device to enable Xzar and/or Montaron to be in your party.

The "Thieves hold a knife to Jaheira's throat" thing is a part of the Jaheira Romance.

"Jaheira returns to Harper Hold" is a part of Jaheira's Harper quest.

Apart from turning someone like Minsc into a Human Roadblock as LennonCook suggested, the only way back into the Harper Hold is to have Jaheira in your party--unless you've already whacked Galvarey, in which case the door will be unlocked, and stay that way.