Viewing a history listing
The fact that Gabor was appointed Reader in Electron Physics at Imperial College in 1948 can be read in a document from the Imperial College Archive titled: "List of Papers and Correspondence of Dennis Gabor, 1900-1979", compiled by Jeanne Pingree. You can also find there an outline of Gabor's life. That document is available at: https://workspace.imperial.ac.uk/recordsandarchives/Public/Gabor,%20Professor%20Dennis%20FRS%20catalogue%20of%20papers.pdf
Of course, all my comments do not imply any doubt about the well-deserved recognition to the Milestone.