Waun Maes sheepfold -- or is it?

The north-western segment of the "sheepfold" wall -- very ruinous and very old, and heavily colonised by lichens.

Paul Sambrook's map showing the ruinous enclosure and the other enigmatic features in the neighbourhood.

This strange feature was referred to in an earlier post, and today I had a chance to visit it by splashing across a very soggy bog from a parking layby on the main road.  It's actually located on a stony and grassy rise extending northwards from the slopes of Foel Fach, so it's in a well-drained and relatively friendly environment, with the headwaters of the Gwaun river just a few yards away.  There is plenty of good grazing land both to north and south of the "sheepfold."

The small rectangular enclosure inside the western part of the periphery wall.

The southern part of the perimeter, showing the very large boulders used, and its ruinous state.

The enclosure is very large, about 40m north-south, and over 50m west-east.  It has one rectangular feature inside the western wall and another smaller rectangular feature near the angle in the eastern wall; might these have been shepherd's shelters?    There are a couple of quite narrow gaps in the walls -- but were they ever big enough to have been used in connection with the herding and containing of sheep or other animals?  For the most part very substantial boulders have been used -- some of them are over a metre long, and moving them must not have been an easy task.  I have some doubts that these walls ever were high enough and tidy enough to have held sheep -- for that you need a vertical wall almost 2m high.

Within 100m of the enclosure there are a number of "platforms", mounds and signs of stone arrangements, and the most prominent is a a ruinous "long hut" which must have been rectangular and which is now largely covered with turf. Shepherd's hut, or something else?

The remains of the "long hut" near the eastern bank of the river.

I'm mystified by these features. Could they be prehistoric, and connected in some way with the features on Waun Mawn (which is after all geographically very close by) and on Banc Llwydlos and Brynberian Moor?  Might they have had something to do with the medieval deer park?  Or do they date from the modern era of sheep farming on these wild and forbidding moorlands?