It only took a few minutes with the Ege Fifty Original Leaves website of Denison University to not only confirm that this was leaf no.3 in the portfolio, but also to identify that the page reproduced in the von Scherling catalogue is now at Cleveland Public Library:
This also happens to be the very same page that is visible to the extreme right side of the photograph at the top of Ege's infamous article "I Am a Biblioclast", published the year after the Rotulus catalogue, in 1938:
The page that faced this one in the bound volume (partially obscured in the image above) is the verso of a leaf now at the University of South Carolina:
The significance of of my finding the manuscript in the Rotulus catalogue is that we now have a fairly detailed description of the manuscript before it was broken-up:
We can also deduce from the description that the book was in quires of 8 leaves each, because it tells us that with five individual leaves missing, and with a single quire missing at the beginning and end, there are 21 in all missing (21-5=16, so each quire must have been of 8 leaves). This allows us to reconstruct the collation of the whole volume, and work out where the currently-identified leaves once belonged.