Found it! The 1:7500 print I took from MAGIC helped! Basically, go up the path by the side of the house, and continue until you get to another gate. Go through this gate. On the right is a smallish enclosed field. The hut circles (as far as I could see) are in the next field beyond this. Stay on the path.
The hedge on the right eventually opens up to an area of bracken and gorse. There was a trodden path through this that I followed, that led directkly to a large upright stone, hidden in the far hedge.
Take care, as the disused quarry starts in the adjoining ‘field’, and may be the various stones that purejoy found.