Sadly, some of these do leave a bit to be desired but we usually end up adapting them so they are better that the manufacturers intended!
Bespoke can either be in the form of a brick and block construction or more usually a timber frame. The level of habitability depends on the client’s needs so we can tailor the build to the client's individual requirements. Insulation, power, sanitation, water supply are all considerations that will need to be addressed.
Why not have a sedum roof on your garden building. (or your extension?) They are ecological, look great and are really straightforward.