There are hundreds of large ant mounds in the woods made by these ants, often at the base of trees, and often a couple of feet high.
No interactions present.
I think it would be best to enter an ID of just Formica, as there are similar species and hybrids to deal with. Separating them without a chemistry set would be extremely difficult.
Chris Brooks - www.dragonfly-images.co.uk
My Flickr site - www.flickr.com/photos/ceb1298
Roll on the chemistry set...
Lat/Lng: 51.0822, 0.0357
OS grid ref: TQ426334
Very approx location