We were there in June 2014. Good to see that someone had cleared up some of their eyesore mess in the meantime
The grass in Gerald’s photo is like the grass in my photos from 2007. There was no compound up there then. The grass in Richard’s photos is like some 2018 photos on Geograph. That leads me to conclude the fenced off compound was built after October 2007 and removed before 2018. They were starting a big expansion of the windfarm in 2007 so it may have been something to do with that.