In their reply the NT suggested that they were aware that the same effect could be produced with computerised special effects. Well surprise! But why didn't they insist on that instead, and try to claim some cash off channel4 for the use of the image anyway? For the sake of a couple of grand?
They also suggested that the publicity for the White Horse and NT would generate more visitors (and therefore income), so I still don't see the need to deface. The most likely outcome of which is probably to plant the idea into the head of some moronic vandal to emulate it on other heritage sites.
As for Big Brother.. I take the same view as Winston Smith's cellmate - Fuck Big Brother!

Rab