What was the purpose of that action? To seed shock and "ruffle some feathers", sow disbalance under the coat of "shaking sleeping people up".

A goal at which it has singularly failed. There'll be a bit of noise in the papers for a day or two, Stonehenge will be cleaned off with "No harm done" and life will move on with no useful change.

Their stunts were effective the first time or two, but now are largely ignored or even just cause irritation.

If they, indeed we, want to change the trajectory of human caused climate damage we need to build bridges at the community level and bring people together to force the hand of the political class. These stunts don't do that, they just give ammunition to those who seek to prevent positive change.