Visited this fascinating site today and just thought i'd add some tips for anyone else wanting to visit it. The coordinates were pretty much spot on I think, just don't make the mistake we made and approach the site from the top of the hill, it's far easier to find when you're walking up the hill!
Park up in Lordenshaws car park and take the path that heads straight up Simonside hill. When the hill starts leveling out, head to the right towards the scattering of rocks on the flat area. Thompson's Rock is easy to spot, it's the biggest there.
The trial stone is another large rock, to the east of Thompson's Rock. The deepest hole of the trial stone is near to the ground and gets covered with plants so might take a bit of spotting.
This holed boulder is shown in this month's 'Fortean Times' and I see it's been mentioned on this website before (I took the grid reference from Gavin Douglas's post here.) The 'observations' page has some photos of the sun shining down the hole through the stone. Perhaps it really is aligned, perhaps some prehistoric people wriggled it round until it was facing the right way. Whatever, it's a pretty curious object with that hole right through it. It surely deserves some weird folklore (Richard Cox in the FT makes a comparison with the Stone of Gronw in the Mabinogion). But being off the beaten track maybe it's been lying low for a few tens of centuries, there on the flank of mysterious Simonside.