He's an archivist. I can think of ways in which Kay might have encountered him via academic routes: for example, he might have been teaching palaeography (though I wouldn't have thought that even at Oxford undergraduates would be studying this in their first year, but who knows?) or there might well be instructive student visits to the archives. Perhaps there's some kind of system of students volunteering in the archives? But it all seems to have happened extremely fast.