When I interpret this song I think about the double, rather triple, meaning of the word 'keen'.
Having or showing eagerness or enthusiasm.
Wail in grief for a dead person.
An Irish funeral song accompanied by wailing in lamentation for the dead.
I think Roy is a window-cleaner who always looks happy to his clients "Smiling on time" "Romancing you" trying to get his clients to think he is happy so that they'll keep hiring him. To them he appears to be keen and eager to work.
But in truth, Roy's life is very mundane and he is actually quite depressed. While he looks keen on the outside, he is keening on the inside.
"Even when it's under your nose well, you just can't see it, can you?" Even though it should be quite obvious that Roy is depressed, his clients just can't see past his fake happiness.
Prehaps Roy is so depressed that he kills himself and this song is also 'Roy's Keen' as in Roy's funeral song.
When I interpret this song I think about the double, rather triple, meaning of the word 'keen'.