I agree, these two sites should have separate listings.
The Lyneham Longbarrow is at SP297211.
The Hoar Stone depicted, at SP378237, should be called `The Hoar Stone at Enstone`. There are other Hoar Stones.
For instance, at Steeple Barton, 5 miles to the east, there are two Hoar Stones, which can be very confusing. James Dyer, in his book Discovering Prehistoric England, gives the location of one, but his description is of the other!
baz