I have emailed the National Trust and circlemakers. Just got C4 to go.
I got the stuff about the residue still being there from some bloke called PeteG, here... http://www.stonepages.com/forum/index.php?s=282e841ef92746db858431d7a71e5151&act=ST&f=4&t=478&st=0&#entry2017
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