They are strikingly similar though. The first time I went through Oakley Down cemetary was at a sprint back from the Dorset Cursus due to a veritable torrent of rain.
However the ring barrow to the North of the cemetary was enough to stop me in my tracks because it looks so much like a henge. 10 seconds of staring and then sprint on. No entrance to that one though.

I thought ring barrows marked graves of women? Is that right?