I found a very interesting site called Derelict London. One of the photo's is of a sculpture embedded in an arch of a sort of imp. It is in the Parkland Walk, a disused railway line. It ran from Finsbury Park via Stroud Green and Crouch End to Highgate. The sculpture is sited as you approach Crouch End Station. The photo taker says he doesn't know anything about the sculpture, but I'm intrigued and would love to know. Anyone?