I have ordered a large mobile field shelter which I can gate off, and section for the moment, while I give this some thought. Neighbour up the road has a big open fronted barn in her stable yard, its high, and big bays. Bit wasted as all she has in it is a few bales of hay, and the farrier uses it for shoeing. Not very good security wise, as it faces the road, and all can see in, as they drive past.
Thank you for all your ideas - keep them coming.
If I lived out of sight of a road, we would build our own, and although we are in the country, the fields can be seen from about 20 miles away, as they are high up!!