There's a diagram of the markings here:
http://www.rupestre.it/images/millt001_06.jpg
I saw this one on europreart.net, that's where I read about the possibility that the stone may have stood. There's a still standing stone row with a decorated stone somewhere on the Dingle peninsula also.
I also found it partly because of the fence visible in O'Connors photos on that site is visible through the gate as you pass!