I tried drawing it in two different ways, Dave.
First, as a series of separate components - corner post, roof, arch lintel, window frame elements, etc. It produced a terrible print, even though all the sub components were solid, and (I thought) butted tightly.
Then tried by starting with just two components - the roof, then a set of four vertical walls, which I then carved holes and grooves in using a mix of pushpull and Intersect Faces - the result which you see.
The result kept becoming non-solid, and I simply couldn’t fix it properly.
I can’t recall ANY other model I’ve had so much difficulty with drawing, and I still don’t really understand where or how it went wrong. I was using careful inferencing wherever possible, and have always modelled with Length Snapping off. But SU would frequently just not snap to an existing corner or edge, in spite of modelling at 1000x full size.
The end result in print is fine, but the underlying model is not, and I simply couldn’t fix it.