With the grass and other vegetation so high at the moment this is perhaps not the best time of year to visit this site. The ruins of the church are totally invisible and the bullaun very well hidden.
The bullaun stone is at the west end of the ruins, which are only denoted by a small group of trees at the road side. It is a very rough stone and the bullaun too is very rough.
From Enniskerry take the R760 south and then the R755 south. After about 2km turn right and pass to the south of the Great Sugar Loaf Mountain. Continue until you come to a left hand turn just after a sharp right bend. Park here. In front of you there is a gate and beyond that a copse of trees. The bullaun stone is in the center of this copse about 10m from the road.
This is an explanation of (and a bit of a disclaimer for) the coordinates I provide.
Where a GPS figure is given this is the master for all other coordinates. According to my Garmin these are quite accurate.
Where there is no GPS figure the 6 figure grid reference is master for the others. This may not be very accurate as it could have come from the OS maps and could have been read by eye. Consequently, all other cordinates are going to have inaccuracies.
The calculation of Longitude and Latitude uses an algorithm that is not 100% accurate. The long/lat figures are used as a basis for calculating the UTM & ITM coordinates. Consequently, UTM & ITM coordinates are slightly out.
UTM is a global coordinate system - Universal Transverse Mercator - that is at the core of the GPS system.
ITM is the new coordinate system - Irish Transverse Mercator - that is more accurate and more GPS friendly than the Irish Grid Reference system. This will be used on the next generation of Irish OS maps.