Hello ADC,

I suggest that part of the problem here is the fact that this grill was not fixed to the Passage floor - as one might reasonably expect - but on top of a block of granite that partially filled the Passage from the floor up (this block was known as " Petrie's granite block")
IMO this arrangement and the limitations imposed by the Edgars' photographic equipment and the then prevailing conditions resulted in a distorted appearance of the grill door.

In volume one of John and Morton Edgar's The Great Pyramid Passages and Chambers pages 197, 198 and 199. Glasgow 1923, are three photos of this part of the Descending Passage with this grill door in the background.
To my inexperienced eye it does look as though two of the three photos have had the door highlighted in some fashion.

MJ