I have come up with an emergency solution in case he carries on with his demonstration of not leaving the playpen at midnight (lastest) during the week.
I have DIY ed a bottom on his playpen mch and cut cardboard into squares to catch the pee (as you can see on the template it works) the chamber is filled with bedding and his hoard. So I can leave him in the playpen and in case he gets tired he has his house. When I get up at five he will willingly go back into his cage, as he will be tired.
I have had to use this solution once before, as there was nothing I could do to get him back in the cage (he hops on the wheel and runs like the devil as he knows I can’t get him then).
I hope he stops his antics and willingly comes out at midnight at least I get my five hours sleep, if not I have an emergency solution.
And no he won’t try to climb out of the playpen, he loves it in there! He has all he needs, a wheel, water, food, a mch two hideouts and toys.
He just can’t burrow, but it is only a temporary sleeping spot.
I have prepared the house

and cardboard pee mats
View attachment 14084
View attachment 14085