It arrived today.
It's massive. It just fits a gap on my floor. I now need a bigger room.
I think it will fit through the loft hatch, but it's going to be hard to get in. The fixed ladder makes it hard to get the right angle and the cage length makes it hard to get past the top of the door frame. I might do a full level, but think access to the bottom could be an issue with the two small front doors, so may have an extra platform on the right hand side and possibly one alone the back (possibly a bridge shaped platform.)