So, heres the thing.
I had an idea, beginning to wish i hadn't, this is the semi circular roof above the lift/stairs

the idea was, this roof should also be clear, and this is what i came up with, not perfect, but i like the look.

At this point it started going down hill. i put the main roof back on

So after several hrs work creating the glass dome it was ruined by the roof.
So i opened a new plan, recreated the walls and floor put a semi circlar stair in a measured (guessed) position, exported- imported- changed thickness- exported - imported added pitch, and came up with this

progress, a little tweaking, a couple of walls, should be fine.
But then i tried the walls

Short end of the wall (set at 1/8") is too high and the curve is wrong. [:(]
Heres an image of my next idea.

Can anyone out there help me with this last image please, the ideas have dried up here, thx