We found the stone after a little searching around in the undergrowth.
Park in the social club car park and walk towards Marston Mortain on the opposite side of the road to the houses (with the church in the background). Enter the park through the first stile that you come to, turn right and walk through the long grass for approx 30-40 yards until you are opposite number six Station Lane / Jubilee Cottages (?) - hard to tell where one starts and the ends.
The stone stands approx 20-24 inches in height and is concreted in place, kind of octagonal in shape.
I parked spot on the grid ref given, but couldn't see the stone anywhere. There's a footpath leading behind the houses, but nothing to be seen there, and a footpath on the open ground on the other side of the road. I drew a blank.
Any specific directions to find the stone would be useful (unless the grid ref is actually wrong)
Henry Bett gives a different version of the legend in English Legends (1950). he says that the Jumps Inn, on the road to the church, was so-called because on the spot where it stands three youths were jumping on a Sunday when a mysterious stranger joined them and offered to teach them how to leap. He made three marvellous leaps, the extent of which, says Bett, was still shown (presumably he is referring to the standing stone or stones). The terrified youths tried to escape, but the Devil seized them and they all vanished in a blue flame.
Retold in Westwood and Simpson's 'Lore of the Land' (2005).
The legend I've read about the Marston Moretaine church is that the division of the tower happened when the Devil was trying to steal it; it was too heavy for him so he put it down and left it. Great story!
Burl mentions the site in his book about stone rows 'From Carnac to Callanish' - a man was playing leapfrog on a Sunday, and the devil turned him into stone by leapfrogging over him. You wouldn't think the devil would care about Sunday leapfrogging.
Whatever, it is very unusual to find a stone row in this part of the country -or even a single stone, in amongst the brussels sprout fields. Burl is quoting Dyer's Penguin book of Prehistoric England and Wales and doesn't mention what clues there are to this having been part of a row, but I'd like to find out some more. Maybe the idea of the row has got more to do with the game and the legend than any archaeological remains? Also, the stone is near Marston Moretaine, which has an unusual church with the tower separate from the rest of the building: this is blamed on the devil too.