I came across this thread which is similar to mine.
The Houston 04 SE
In this thread 78F350 was replacing the tumbler and the whole locking mechanism so didn't mind destroying the tumbler and the lock mechanism to be able remove them.
In my case I did not want to destroy the tumbler, I just needed to unjam the locking bolt, so I dremeled out the part of the mount that captures the little pin.
Pick your poison.
If I had known in advance what my problem was I could have repaired it without it costing a cent.