Ivy was on the box edge for a bit, then away, then back again.  Princess turned up a couple of minutes later, sat on the edge and then followed Ivy into the box again.  They had a wee bit of a "conversation" and then he hopped out and away.  She's had a bit of a scrape, a pick at pebbles and now she just hanging out inside the box.  Spoke too soon, more scraping going on now ...