There’s some good points being raised here – my first reaction was to go and saw the thing down too. You're right though, for zealous Christians , ie the type who put large crosses everywhere, such an act would be seen as the work of pagans, devil worshipers, satanists, or worse – goths. It reminds me of the woman who lived close to Glastonbury who put up a huge cross on her land because to her the festival was some giant satanic gathering with the devil himself walking amongst it. Unfortunately such people are blinded by there own faith (not just Christians by the way – no offence meant to anybody) and view anything that conflicts with their beliefs as a direct attack on them – the chances of getting them to listen to reason are remote. Informing them that the place may be important to those of a pagan persuasion would only make things worse – it then justifies their actions, but approaching the issue from a archaeological angle may have a small chance of success and they may listen to the nice little old man in the tweed jacket, but again I think the chances are small. I suspect that the cross is probably there to stay, especially as EH are well aware of it and seem not to want to antagonise its builders.
Ho-hum

-Chris