I visited today - just at the moment the stone is extra-ordinarily easy to find with the vegetation quite low -
The pastscape website aerial photo is incorrect and that is where your problems arise - pastscape show the Giants Stone too far W (about 100m too far) -
I have found the best way of a placing a site is to look up http://www.old-maps.co.uk. (see my comments re: Avenis Barrow in Bournes Green 2km SSW) - for this site check out the 1979-1981 1:2500 OS map - it shows perfectly where the stone lies - on that map you will see an equilateral triangle just North of the track passing W to E about 100m N of Battlescombe Farm -
The stone lies in the bottom left hand apex of the triangular field about 5m from the corner (about 3m from the track) - for those who may still have problems one of my photos is taken from the track - mind the barbed wire!
Something is not right. This message is just to keep things from messing up down the road