I just listened to a marvelous old recording of My Lagan Love by Liam Devally,
http://www.youtube.com/watch?v=zNyz-i-q_jI

and I heard that phrase in a way I never had before, as

"...through the door in peep"

That makes complete sense to me and I wonder if we've been talking about a mondegreen all along.

Alice

PS, thanks to lorgain2 for emailing a link to me of Liam Devally on youtube.