I think you might have missed a bit out of that url Bruvs:
http://www.themodernantiquarian.com/site/10832/horse_clough.html#images

Not knowing much about either Derbyshire or chambered tombs, I'd not feel able to comment on those stones. Are there many such things in the area?
It seems positive that the archaeologist you mention could be interested in having a bit of a dig. Hope you find out more.

And welcome to tma! :)