Design and supply detailed building plans for a garden room (studio/pod). Must be familiar with UK building products.

Design a contemporary stand alone garden room for use as a home office and a place to retreat from the main house for some peace and relaxation. I may be building a number of these so things to bear in mind would be: I am looking for a building that is modular, quick to erect on site without the requirement for any wet trades on site. I have experience in building so I will be doing the work myself, I also have a very large workshop with many woodworking machines so could make panels and such off site. Built on a non permanent foundation such as precast concrete pads or something similar. The buildings will be approximately 6 meters long X 4 meters deep X 3 meters high with a flat roof but could be larger if required. The exterior of the building needs to be maintenance free as in no painting required for at least 25 years, bear in mind no plastering (wet trades) outside or inside. Most important the building has to be suitable for UK weather conditions, exposed costal site wet and windy.