The quest does not automatically clear if the players taking the quest log off without finishing/cancelling it.

Last occurence, 2 players had taken it and the quest was locked despite both being offline.

*edit* Confirmation - happened again, this time with a single PC

Yeah this is quite a common occurence and unfortunately for the Aussies quite often no one is around to reset it.

Seems a popular one for people attempt - can't get through but not sign off from the quest.

Anything that can be done to repair this would be great

Fixed.