Hi there Paulus.
I was wondering where you got your info about Robin Hood's Stone from. You say that it was formerly part of a stone circle called the 'Calder Stones', but the Calderstones are now perceived as a seperate site (originally a burial chamber):
http://www.themodernantiquarian.com/site/248
The photo you've posted is definately the right stone though. Very interesting to see it in its original position. Have you got any more photos?
K x