[DogByte6RER]

The article referenced the stone being put in place about 4000 years ago, or around 2000 B.C.

I cannot elaborate about the direction or degree of angle ...

[Lonesome in Massachussets]

South is more or less the same direction today as it was in 2000 BC. The British term "midsummer" refers to the date of the June solstice. At the solstice, the sun is as high in the sky as it ever gets, but the height does depend on the era.

As shown, the sun, at the summer solstice was a little more than 0.4 degrees higher in those days than now. (And ~0.4 lower at the winter solstice.) The variation in the height of the noon day sun changes very little from day to day near the soltice, less than 0.01 degrees per day the day before and after, so this instrument would only have yeilded, at best, a vary crude approximation of the date of the solstice.