The two smaller stones are easy enough to spot when approached from the track but the large square boulder on the rise of the hill really draws the eye. If my map reading is correct then the alignment passes northnorthwest just below, and following the line of, Birchen Edge, across the top of Gardom's Edge, shaves the western edge of Swine Sty and onto White Edge. Whether this alignment was deliberate, part of a field boundary, or just a coincidence and the two small stones formed part of some other structure seems open to question but the alignment theory seems wholly believable on site when standing behind the smaller stones.
The grid reference for this site seems a bit inaccurate. I found the 2 smaller stones, each 45 - 50 cm high and 3 paces apart, at GPS reading SK 28255 71378 with the larger stone, 115 cm high, 100 paces away at SK 28225 71454.
There are lots of stones in this area and it is tempting to believe that many others have also been erected. When standing at the larger stone another possible alignment suggests itself looking east to a stone 45 paces away at SK 28265 71450 and a third stone another 20 paces further at SK 28281 71446. The former is leaning over a bit with its top 75 cm from the ground and the latter is 60 cm high.