Fortunately I keep my eye on the kittens when they are out in their pen. I couldn't see Sooty not usual as they are sometimes just out of sight from the kitchen window so I pop out to see where they are.
I could see Sweep re-action which was very alert, hubby was nearest to the side door, in a panic I said Sooty has got out. Hubby was so laid back he can't get out. I struggled passed and flew out to find Sooty and Duke together on the side path.
I blamed hubby saying the gap was too large at the bottom of the pen he said it wasn't, I then thought Sooty had dug his way out, I had visions of using paving slabs for the base.
I put Sooty back in the pen and watched, he got out through the gap between the house and the cage

the bolts were loose and the cage had moved away from the wall. Both hubby and me push it back into position and hubby secured it.
Even if the bolts had have been loose how did the cage move. My thoughts are that someone has tried to take it. I can't see that the cage has moved due to the wet weather as the legs of the cage are standing on a solid area.
Very strange but a happy ending.
Sue