We parked up the lane from the property with the chambers, at an empty house that was being renovated, then a short walk down the lane and up the drive of Tan-y-Muriau house we knocked (no choice really) but no one was in, we did see the donkey and the dog that had harrassed poor old sam last month but they were locked up.
Iv'e got to say if it wasn't for sams photos I wouldn't have known what a small wonder this place is so hats off.
The big dolmen is a good one and one can just about sit comfortably inside but the other chamber has slipped and collapsed, so glad I came without the bracken.
Amusingly, the farmer has placed a "Watch out, Cairn about" sign on his gate (referring to his dog and not the chambers). Ask the farmer and he will direct you to a stile leading into a field of bracken.
This page contains a section on Tan-y-Muriau (aka Rhiw Burial Chambers) including photos, a description and directions (which I could have done with when I tried to find the site in back in 2000).