Thought I answered this one twice already.
IN one of the forums where you posted. I linked to my suggestion. A fuel door..
These do not have the cut out for the cable to exit when the hatch is closed but you could easily maching such a cut out in and then mount the plastic door to the metal one so you use it's sliding or moving slot cover.
Also, I have such a hatch I use to pass my Cat-5 to the Wi-Fi modem up the flagpole.. It is 8 years old and no tribble at all. Different kind of hinge (Pin type not flex).
Home is where I park it!