"Its contents include detailed stone carvings of a human head and a sheep's head."
Oh aye? I must have missed those... Anyone?
Here - http://www.stonehenge-avebury.net/aburysites.html#WK I have to say I couldn't really see it when I looked.
Which begs the question - that's stated as fact in a lot of places, as is the face at Stonehenge. Are they real? I'm totally unconvinced myself, but that's the trouble with the internet, there's nothing to measure assertions by.