There is a blade needed to turn the pot however it is offset from the center and rotates around the indentation in the center of the pot.
The second photo makes things much clearer - thanks.
What a pain of a design!
It appears that the whole top rotates when it is adjusted (I think you mentioned this somewhere earlier).
So....
We've been trying to find/work out a tool to fit inside - what about we flip that idea and rotate the pot from the outside edge with some fine pliers/tweezers? A bit more tricky but it might be simpler than trying to get/make the proper tool (if the whole mechanism rotates, making this possible).
It all depends if you have a fine enough tool and you've got enough room to get it onto the pot (looks a bit tight from the original photo).