Thank you Blueray, Cypher, Boris and Thin Lizzy
Yes he has chewed a massive hole in the carpet in that corner - had a go at it a few times. I really should have put something down on the floor! He does it when I leave him alone in the playpen for 10 minutes or so. The toilet roll was a treat cracker and he enjoyed that! I now have a ceramic pot in that corner. He doesn't seem interested in the other corners, just that one.