Thank you
Yes he does look happy in that little donut bed
The wheel idea wasn't mine - I think it was Leedshams and others who first did it
I did actually try using a house underneath for the wheel to stand on but the wheel was touching the roof of the cage! I guess the other alternative is to glue legs on the wheel base.
It is strange to see him grow so quickly! He has quite a cosy nest now - but still on top of his toilet. He is peeing in the other room so will add a toilet there.