Was thinking about a highseat for a certain location. While it is not ideal for a full freestanding it is difficult to impossible to use a lean to. You would need to prune back so many trees to sight left or right, unacceptable to the owner.
I spent 20 years in timber building manufacture and timber prefabrication. I now in retirement like to play. I have constructed several designs for ease of use and simple transportation on my own. The following is my latest creation. Approx cost £35
used 3 lengths 3x2, 3 l3ngths 2x2 supplemented by a few offcuts from under the bench, one length 150x22mm sarking. some windbreak material, 5 hinges, screws and 4" coach screws.
It has a bay window type wind break to increase leg room and is basically a triangle with each side 1100mm.. It is designed to sit flush with the edge of the wood and a guy rope from each leg is used to stabilise the structure. It was reasonably stiff with just two light tent gut ropes tied to the shed.
The bottom rear rail and the seat lifts out, the floor hinges up for entry and for folding the structure flat for transportation. I can carry the structure myself but it is designed for two persons to place it into the required area. . I will update when I find a suitable location.