Having been a civil servant, I wish to point out that regarding the Department of Education and Science, people may have no concept of the vast quantities of papers and files that exist in Departments. It can be quite difficult to find papers from as recent a period as two or three years ago, let alone several decades ago. In theory, there are supposed to be good filing systems, but files were stored hugger-mugger in cellars and other places in the past. One could underestimate the amount of resources and personnel required to find particular pieces of paper from long ago.