Start from a template
Every one is a real building — framed, clad, and sized under a planning cap. Open one and change anything: it is a starting point, not a finished design.
Up to 2.5 m high
Permitted development lets these sit right against a boundary, so no strip of garden is lost behind them.
Over 2.5 m high
The extra headroom costs space: permitted development needs these 2 m from every boundary.
None of these? Start from a blank 4.80 × 3.20 m and size it yourself.