THis chambered tomb which is on this site but with no pictures, you have to follow the link to see photos, is an interesting site. It has supposedly the largest capstone (60 tons) collapsed, is presumably sighted on Preseli mountains and a midsummer sighting from one of the stones. There are two other tombs nearby, (Parc-llyn Ambleston and The Altar Colston) and about 8 standing stones mentioned on RCAHMW, but their grid reference numbers are a bit suspicious.
Could'nt find a circle nearby but felt that there had to be one. Looked at Burl and there is one a mile away at Letterston. Apparently according to him, when the circle fell into a ruined state,
a large barrow (with urn burial inside) was piled up over it. The circle was small 12.2 metre with 20 stones. Chambered tombs is this part of the world fall into inland or coastal, some are "hidden" because of presumably, proximity to Ireland, where they get a lot of their influence. The circle here is embanked, similar to Lough Gur.
Moss