Design looks OK. I'd want to see internal shots too. Also the weatherproofing is only from the surface coating and I've always bought houses made from pressure treated timber because I believe they last longer (and require less maintenance although I have painted all of mine too). My only other little niggles would be felt over the nestboxes and the height. I had a red mite infestation in my layers house and tracked it down to the felt over the next box so I've stripped it off and replaced it with onduline. Thumbs up for the onduline roof! Re. height, I'm 5ft11in so a max height of 5ft 8in would annoy me - just not quite high enough stand up in. But most of my housing is lower than that so it is a niggle - mostly you're cleaning them out so being low is not a problem because you're on your hands and knees anyway. Just I quite like cleaning out my big 'normal' sheds that are the same floor area as this but with 7ft height.
H