A couple of weeks ago, a friend had trouble getting her port off her Nauticam housing. She had all kinds of expert help, and they finally got the port off with a screwdriver. Today I had the same problem with trying to remove a port from my Nauticam housing that she had. Untypically, I was careful and did not damage the port/housing, but I could have. In my case, I would have severely damaged the housing. I'm writing this so folks know about this and so will not damage their housing if this occurs.
The Nauticam port lock uses a gear to slide locking flanges over the port's bayonet ring. If those gears inside the housing (easy to see, in the bottom right side of the front of the housing) don't move all the way to let the port's flanges out, then there's no way you are getting that port off. If you take a screwdriver to the port, you will damage the port and housing permanently. In my case, an allen screw that kept the port lock gear attached had gotten loose, so the port lock was not opening the flanges all the way. I had to experiment a bit, completely unloosened the screw and gear, to see how the plates needed to be in order to release the port. Then I removed the port and put the gear back on.
I'll try to post photos of this.