It has to be mounted on an extra sheet of card because- as many elderly sheds found out- a 45XX wouldn't go into it! It does now-just. The extra foundation will be trimmed a little and a hut will be joined to the rear quarter when planted. There is also the matter of an access ladder, I have some but until fixed this won't be attached.
I looked at the vents atop the building and eventually, after scrapping much card and plastic, a brainwave. I had some featheredge plastic card- from Evergreen I think-so pieces were cut and filed to size and glued in. Then the whole lot was painted and is ready to become attached to it's new home.