I've looked through a few hundred photos on my PC and only found three which show the inside of the hatch ( I have not looked in the books as yet), this image is the clearest I have.
Unfortunately I can't post the full image.
I can tell you it is a 38M Toldi II (B20), the unit is unknown at present.
There is another photo that clearly shows the three tone camouflage scheme was also applied to the interior surface of the hatch.
The hatch has what appears to be a slide/stay mechanism on either side, I suspect the locking handle was on the inside of the turret and 'locked' into the slide when the hatch was closed. I have seen these 'stays' disconected and the hatch almost lying flat on the turret roof.