Finally succeeded in deleting a delegate from outlook. As per this post where the delegate remained in the permission lists I had another user who had the same disabled person as a delegate and I was unable to remove the deleted person. Seeing as though the kind of people who have delegates are managers (in this case the head of the company) I really didn’t want to mess around with deleting the mailbox and recreating it.
However, it turns out that by re-enabling the disabled user, creating a mailbox for this user, logging into outlook as the person with the problem meant I could then delete the delegate for good. Then it was delete the mailbox and the user again.
Update See HelloMate for a script that will list who has delegate access in AD. By using this, I should be able to modify our disable user procedure.
