University of Cambridge has a bit more on their "appeal" site (https://www.cam.ac.uk/stories/DarwinAppeal)
The digitized notebooks are available:
[1] https://cudl.lib.cam.ac.uk/view/MS-DAR-00121/1
[2] https://cudl.lib.cam.ac.uk/view/MS-DAR-00122/1
Also, yesterday was the anniversary of the release of On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life on November 24, 1859.