Photo by Alvin Langdon Coburn: interestingly, of the barrow in its pre-restored state.
Another at
geh.org/ar/strip27/htmlsrc/m197926730002_ful.html#topofimage
and scroll down on this ‘Clonehenge’ page for another pre-’restored’ photo, which purports to be of WKLB too.
replicahenge.wordpress.com/tag/pete-glastonbury/