Welcome Jonathan, I see Silbury has inspired you to write a reflective poem, it will be added to this enormously long stash of megalithic poems.
I've just found, Jeremy Hooker's "Soliloquies of a Chalk Giant" Its the Cerne Abbas Giant....

Totem;

Where are the giant's people?
They have followed the mole
Under mounds. The Dance
Is a ring of stones.

Soon there will be nothing
But a breeze gathering dust
Over pale fields, a maze
Of ditches scored on the hill.

Unless a man stand naked
Of all but imagination.
Let him discover me.

I rise through him
Or lie here and wait,
Scratched in the chalk.