"its huge surface entrance cuttings across one third of the World Heritage area)."
Would that be the Stonehenge Bottom entrance to quote; "except for 9 metres high (at Stonehenge Bottom) embankment covering tunnel visible from Stonehenge.. and to go further... less expensive than Published Scheme but a visually intrusive embankment covering.. so, there will still be traffic seen trundling down to Stonehenge Bottom and the tunnel.