Thank you Coco. Yes he has settled nicely to the changes and I am more relieved everything is at floor level. I moved his food dish to the top of the labyrinth house as a "shelf" which may be why he moved back in there. I tweaked the rainbow bridge so it's the right angle for him now when leaving the piece of cork in front of his wheel
When I clean the wheel next I am thinking of putting that back on its stand instead of screwed to the bars. Now everything is a bit lower it bangs the cage base a bit, although Nugget doesn't seem bothered! It means it will stick further out in the cage, but also means he'll have a secure hidey place under the wheel again that won't collapse. Unfortunately his burrow near the wheel caved in when I was spot cleaning -probably another reason he moved back in the labyrinth house! Honestly theamount of hoards -all over the cage base! I think I'm feeding him too much! He never seems to take much from the bowl, but there were masses of hoards all over the place! The one in the labyrinth is still in tact under his nest in there - it was clean and dry when I spot cleaned that end the other week so I left it - it was so neat and tidy. Had to remove most of the others as he seems to pee in different places.
Anyway I think he's finding it easier to get about. He behaves as if he doesn't have anything wrong with him.
If the pressed down lower Fitch doesn't help much I may put a hemp mat over the top of the fitch so he has a level surface but not a bare-ish cage base.