active Disabling default scenery

[SuburbanFox]

So, after several hours of banging my head against the wall and tearing my hair out in frustration, I finally got Stonehenge to appear in the game. However, it appears my efforts were so effective that it actually appeared twice! (see screenshot - this is actually closer than you can get to the monument in real life... )

 

Impressive though that is, I would prefer it if only one Stonehenge would appear, as I'm pretty sure there aren't two in England there may well be other stone circles but they are not 100 yards from Stonehenge. It looks like the game is importing both the add-on and the default game scenery, however I can't disable the default scenery because the game tells me it needs it, so how do I get it to remove the base FSX scenery (where applicable) and just have the Orbx scenery show up?