[Pebbles82]

I just had another look at your picture - it could be an idea to move the cardboard box on top of his house and free up a bit more floor area as well. The black shelf could be moved up higher so you can have the deeper substrate and still have space under the shelf.

I'm not sure how he gets up to the house roof or the black shelf either from the photo but I reckon the left hand hanging ladder could work really well if you attach it to the left side of the cage, so it goes across the shelf and down onto the floor - as a kind of ladder up to the shelf. A bendy bridge over the house door would give access on to the house roof.

When I got Charlie's first cage I got the access all wrong lol. I found he was climbing bars to get to his shelf and realised the way up was a bit blocked.

A few little adjustments might make him feel a bit happier in there and then the bar chewing could stop - see if it helps. But they definitely can get stressed if there isn't much substrate in.