Just to confirm it is the white undressed stone standing some 10m north of the old windmill. Not sure what the standing stone next to the ruined building is, but it is typical of the Anglesey stones being broad and thin. If you are inclined to climb over the fence behind the building is a narrow track/green lane which leads to a field perhaps 30m away. At the end is another "standing stone" forming the gatepost. 6/9/06
The small lane up to the old windmill is hard to pick out on the main road. We got there, 3rd time lucky. Just before the renovated windmill we saw the first stone and took about 10 pictures. I wondered why it was so close to a deralict building and saw two holes with wood still filling them.
Further up on the hill top we saw the other lump of a stone, half covered in ivy with great views. This, I decided, was it but I posted a pic of the other one as well, just to cover all bets.
The eight figure grid reference for this site is SH26647888 according to Coflein.
It's described as, "an undressed, erect monolith, 1.6m high by 1.4m by 1.4m". The National Primary Record Number (NPRN) is 302269 in case anyone wants to run a search for it.