Threnody. Dirge. Lament. Epitaph. Elegy. Wake. There are so many English terms to describe the passing of people and things that you wonder if introspection about demise might be a national characteristic. All these words are on my (doggedly cheerful) mind as staff have moved out of London’s Design Museum, securing the last open door with a padlock on 30 June and leaving inside cavernous spaces with rusting memories of designer people and designer things.